One evening, when I was 11 years old, my mother sat down awkwardly on the side of my bed and picked up the small, green pillow I had slept with since I was a toddler. The pillow, which I had inexplicably named Lauren, had hens and baby chicks embroidered on it, as well as one manly looking rooster. My mother placed Lauren carefully in her lap, looked up, and asked me: "Emily, are you sexually active?" She had heard the rumours that had spread from my group of (not so loyal) friends to the entire school and now, apparently, to the mothers who clustered together under sun umbrellas on Saturday afternoons pretending to watch their children play football.

I didn't answer her right away. I was considering the lesson we'd completed that week in English class on active vs passive voice in writing. Active voice means the subject of the sentence is doing something. For example: "My boyfriend put his hand down my pants, told all his friends I was a slut, and convinced everyone to hate me." In contrast, passive voice means the subject of the sentence is having something done to them: "My body was touched by my boyfriend." "My reputation was ruined by this event." "My life has been destroyed by rumours." For example.

I looked at my mother, who had begun twisting Lauren the pillow into a tight, painful-looking coil. I considered what had occurred that day weeks before, in my boyfriend's best friend's basement. And I answered: "No, I'm not sexually active. I'm sexually passive."

Last summer, while visiting my parents at my childhood home in New England, I came across my old diaries, which I'd kept religiously from the age of 11 through high school. "Came across" doesn't really paint the right picture; rather, that collection of tattered, college-ruled notebooks had been lurking in the periphery of my adult consciousness every time I set foot in my childhood bedroom, which was now only once or twice per year. I sensed those diaries' heavy presence, crowded in on the bookshelf next to the useless art I'd made at summer camp and various participation trophies.

And as I read, I was transported back to that time. A time when boy-band posters were plastered on my bedroom walls and ceiling, when my parents could ground me for talking on the phone too late at night, and when every detail of every conversation I had with the boy I liked deserved to be written down and analysed in excruciating detail. A time when each interaction, each social experience, each feeling seemed monumental and, in some cases, insurmountable.

Emily Lindin as a 14-year-old schoolgirl. Photograph: courtesy of Emily Lindin

On 7 March 1998, I wrote:

Two weeks ago I had the best life! I had everything I wanted and more than I could have ever imagined getting. I guess I was living in this world where everything was perfect, inside this little bubble. All of a sudden, one event caused that bubble to pop and everything inside spilled out, making a huge mess.

I stared in the mirror tonight, watching myself cry hysterically. I've never been in this situation before, where I have no friends.

And Steph… of all people. How could she betray me like that? She said, "It's because you like Jenna more than you like me." I told her that wasn't true, but she doesn't believe me. Can't she see I need her? We were best friends. What happened?

I must deserve this. I must have done something so wrong – well, I've done lots of things wrong. So I guess I do deserve this, and God is just paying me back.

Last night, I felt as if I were living in a dream – a nightmare, I guess. I was seriously considering just killing myself, but then I was like, "Come on, Emily, stop trying to make your life into some dramatic soap opera." So I didn't kill myself.

But everything is going so wrong!

The bullying that led to entries like this stemmed from the day I let my then-boyfriend put his hand down my pants as I lay on a couch, being (characteristically) sexually passive. What could have been harmless sexual experimentation between 11-year-olds became a nightmare as rumours spread that I was having sex with not just my boyfriend, but many boys. My reputation as the middle-school "slut" led to more than one sexual assault at the hands of my peers, self-harm in the form of cutting my own wrists and my mother's anxious, rather unfair punishment of Lauren the pillow. The urgency, panic and isolation that overwhelmed me are evident in lines from my diary, like: "I feel like I've been ripped in half and gutted and then had my guts stuffed down my throat" and "I feel so dead. Out of all my peers that I have ever loved, I've never loved anyone as much as I loved those two. And then they betrayed me… together."

But the moment that sticks in my mind as the most painful came when I realised that my former best friend, who I'm calling Steph, was using the instant message screen name DieEmilyLindin.

I described it in my diary as follows:

A new chat. It was from the screen name DieEmilyLindin and it said, "Hi Emily." I just stared at it and didn't respond. Then I closed the chat box and went to get some cheese in the kitchen.

When I came back to the computer, the chat box was back and this time it said, "Why haven't you killed yourself yet, you stupid slut?" I know it sounds stupid, but I felt like the chat box could see me through the computer screen.

I asked Stacy if she knew who had made that screen name, DieEmilyLindin. She said it was Steph and that Steph had also made a web page called Die Emily Lindin, and that it had been there for six months, but Stacy had just found out about it from Emma. I didn't try to go to the web page. I felt kind of sick, like I could throw up.

Another time, Steph took a "poll" on our school bus, asking the other students to raise their hands if they thought I was a slut. Every hand shot up – at least it seemed that way to me – and I stared at the pavement out of the bus window, willing myself to wait until I got home to cry.

I reacted to this type of attention first by cowering, then by embracing my reputation as the school "slut" and doing my best to act accordingly. My diaries are filled with elaborate descriptions of my flirting techniques, long make-out sessions and every minor exchange shared with the boy I had a crush on that day. I even turned into a bully myself, targeting one of my good friends whose attempts to explore her own sexuality annoyed and threatened me.

On 12 February 2000 I wrote:

Lately, Stacy and Hunter have been stuck together. Like, if you tried to rip them apart, you wouldn't be able to. It's really annoying, because she acts different around Hunter. It is making me have awful urges that I'm able to keep under control for the most part, but sometimes I slip and say something very cruel. Like during study period yesterday in the cafeteria, I was frustrated with my homework. Stacy giggled and said, "Well, life sucks and then you die." I looked up. "Only for you, Stacy." She stopped giggling. That had been my goal. Everyone else laughed, though, even Hunter, which made her face go completely hard. I thought, good. I hate it when she giggles.

It's more painful to revisit entries like this than those in which I am the victim of cruelty myself. In the end, I was lucky. I had motivated, financially well-off parents who enrolled me in extracurricular programmes in the nearest city and encouraged my academic curiosity. I moved across the country for university, and now I live with my partner and work from home writing my PhD dissertation. Life is really good.

But if I were in school today, things might not have turned out so well. None of my friends had mobile phones in middle school, and though we used disposable cameras to document our parties, it would never have occurred to us to scan printed photos and post them online. Now, in a time when phones that can snap photos and immediately post them to social media sites are ubiquitous, the potential for widespread, public shaming can make sexual bullying even more traumatising.

In September 2012, a couple of months after my rediscovery of my diaries, I read about the tragic death of 15-year-old Audrie Pott of Saratoga, California. She was allegedly raped at a party when she was too intoxicated to defend herself; after photos taken by her three assailants during the rape circulated at school and online, she took her own life. That same month, Amanda Todd made a nine-minute YouTube video describing the incessant bullying and violent attacks she was enduring because three years earlier, when she was 12, a stranger had persuaded her to bare her breasts for a photo that was later circulated online. One month later, in October 2012, she hanged herself in her home in British Columbia. In April this year, Rehtaeh Parsons's suicide attempt at her home in Nova Scotia led to a coma and the decision to remove life support. After the story of an alleged gang rape had circulated around the 17-year-old's school, she had experienced online bullying through Facebook and had been sent sexually aggressive text messages.

Hearing these girls' stories reminded me of my own experience being targeted as the school "slut". At the time I hadn't felt comfortable confiding in my parents or other adults. I would have loved to be able to access an online community of women who had survived what I was going through. That's why I decided to share my own diary entries and encourage other women to share their stories. I wanted to provide some perspective to girls who currently feel trapped and ashamed, to reassure them that life will get better.

Fifteen years ago, the type of bullying I experienced wasn't labelled "slut shaming"; now this term is in common usage among feminists and is starting to become more widely recognised. Slut shaming refers to making a woman feel guilty or inferior for her real or perceived sexual behaviour. It ranges from a group of women making nasty comments about another woman's party dress to entire communities like Steubenville, Ohio turning against girls for coming forward about rape. And to the recent case of British judge Nigel Peters calling a 13-year-old rape victim "sexually experienced" and "predatory" while suspending the sentence of her 41-year-old rapist. It's inextricably linked to the proliferation of sexual violence and gender inequality.

It's my hope that The UnSlut Project will be part of a much larger movement to work towards change in our personal self- awareness of prejudices, our interactions with others, and our support of comprehensive sex education and sex-positive legislation. I'd like my own daughter to grow up in a world where "slut" doesn't even make sense as an insult, where the media and communities do not further abuse rape victims, and where a woman can choose to be sexually active (or sexually passive) without shame.

Emily Lindin is making a documentary about sexual bullying and is the founder of the Unslut Project (unslutproject.com)