I am writing this while lying in a semi-foetal position with a cold cloth on my forehead and a heat pack on my abdomen. This is not an ideal position from which to do any type of work, but for me and the other 176 million endometriosis sufferers worldwide, it’s often all we can manage. This is why the updated guidelines from the National Institute for Health and Care Excellence (Nice), released today, are to be commended.

'Listen to women': UK doctors issued with first guidance on endometriosis Read more

These guidelines emphasise the importance of doctors believing their patients when they tell them about their menstrual pain and other attendant symptoms. This seems like obvious advice, but the average time it takes to diagnose endometriosis is seven to eight years. That’s seven to eight years of mind-numbing pain, clotting, diarrhoea, chronic bloating, self-medicating and, often, extremely low moods and anxiety. It’s seven to eight years of potential damage to your chances of conceiving.

It’s estimated that endometriosis affects one in 10 people with uteruses worldwide and yet when I was diagnosed a decade ago, I knew no one else with the disease. I was 20 and had been in chronic pain since the age of 13. While the pain would reach its peak during menstruation, leading to me vomiting and passing out, it affected me all the time. There was sharp, stabbing ovulation pain, dragging, relentless back pain, stinging rushes of pain through my legs and arms. I medicated, then medicated some more, then went to bed for days with nausea and misery, wondering why my body had betrayed me.

Despite all this, I was comparatively lucky because my parents and my GP took my pain seriously. By the age of 20, I had tried every non-surgical treatment available and all that was left was a laparoscopy, an invasive procedure that remains the only effective way of treating endometriosis. I went under for four hours and when I woke up I was shown pictures of my insides, which had been scraped and lasered and prodded about.

It was not a pretty sight. My endometrium – the stuff that’s supposed to stay in your uterus until it exits your body – had spent seven years attaching itself to my bladder, fallopian tubes and bowel. It had scarred my right ovary. If left unchecked, this could have rendered me infertile, not to mention further destroyed my quality of life. I spent a difficult month recovering, during which I suffered from a severe bout of depression (a common side-effect of the surgery) and needed help walking until I could rebuild my abdominal strength.

There are days when I am physically unable to get out of bed (or, even worse, off the bathroom floor)

I experienced around 18 months of reduced symptoms before they began to build up again. I have had surgery once since then and now have a piece of mesh behind my right ovary to prevent it from being trapped against my pelvic floor. When I decide to have a child, there is a strong possibility that I’ll need a third surgery if I hope to conceive naturally.

I have structured my life and my career around this disease. I’ve missed more social events than I can count and recently went to a wedding so medicated that I had to ask the friend next to me to keep me upright during the ceremony. I am the only person I know who doesn’t own a pair of jeans, but what seems like a kooky style choice is actually a result of my near-constant painful abdominal swelling, rendering anything with a tight waistband unwearable. I work as a freelance writer and editor partly because I need a job that I can do from home as there are days when I am physically unable to get out of bed (or, even worse, off the bathroom floor).

I spent my early 20s working minimum-wage jobs in bars, theatres and shops and the only way I got through shifts was by taking double the recommended painkiller dose and secretly throwing up in the staff toilets. Most sufferers are not as fortunate as me. They’re still doubling their doses and throwing up in your workplace because they don’t have any other options. They may not even know what’s causing their pain because the last doctor they saw recommended ibuprofen and sent them on their way.

This move from Nice is so welcome because endometriosis sufferers need to be believed. Treatment is a long road and it only gets harder the longer the disease is left unchecked. From my foetal position on the floor, I hope fervently that these guidelines make a difference.

• Brydie Lee-Kennedy is an Australian-born, London-based columnist and writer for TV and theatre