I wake up next to Ivan at 6.30am. We got a good night’s sleep. Well, everything is relative, but it was good by our standards. Ivan – nearly nine months old – is having night terrors. I mostly end up sleeping on a mattress on the floor of his room, even though the plan was that you and I would finally spend our nights together again.

Yesterday evening, after trying to comfort Ivan for what seemed like for ever, while you sat in the kitchen working, I finally texted you from Ivan’s room. I said I’d have to stay with him again and you answered with a simple OK and goodnight. Not long afterwards, you turned off all the lights, brushed your teeth and went to bed.

I wake up almost rested. Ivan is in a good mood. I lift him up, tell him it’s time to go and wake Daddy. When I open the door, the cat is waiting for us. She, too, seems newly awake. We all head towards your room.

I put Ivan down on the bed so he can crawl over to you, be the first thing you see when you open your eyes. He takes aim for your head but, before he can really get going, I notice that something is wrong. The way you’re lying is unusual. Crooked and bent, in the foetal position, your face pressed against the pillow. There’s also something odd about your skin. It’s paler than usual. Lifeless.

I don’t want to touch your ankle, which is sticking out from under the blanket, but I do anyway. It’s cold. Pale. Stiff. There’s no blood flowing inside. You’re not there any more. You’re dead. I know that, now.

My reflexes take over. I lift Ivan and hold him in one arm while my brain shuts down all my emotions and I start to act rationally – more so than ever before. I call emergency services and when a woman answers, it all flows out in a single breath. Come quickly, I say. I can’t stay here. Ivan stretches for the bed and I hold him a little too tightly against my hip. The woman on the phone asks me to check your neck for a pulse. I tell her there’s no point, but I obey and do so anyway. With Ivan on one hip and the phone balanced between my shoulder and ear, I run my hand along your neck. It’s cold. Lifeless. Again, I tell the woman it’s no use, there’s no pulse, there’s no one there, you’re no longer alive.

I don’t know why I do it, but I grab your shoulder. I turn your body over. You’re heavy, and I almost lose my balance and fall on to you. Your left cheek has an imprint from the fabric of your pillow, and your skin is pale yellow. You’re as dead as a person can be, and I can’t stay in this room another second.

The doctor is coming out of your bedroom, our bedroom. I don’t want to hear what he has to say

The ambulance has arrived and a kind emergency medical technician (EMT) has been in our apartment for a few minutes. He comes back down and tells me I was right, my partner is dead. He also tells me that, if it’s any comfort, he didn’t die in pain – it seems to have happened peacefully in his sleep.

A neighbour is coming down the stairs with her child. I’m in my pyjamas, Ivan is in his carrier, the EMT is wearing a neon-yellow vest with dark green overalls underneath. The child asks his mother who we are, what’s happened. I don’t respond. Nor does the mother. The EMT is silent as well. She hurries past. I stare down at the grey concrete floor. The police arrive at the same time as your brother. I don’t know how he has the strength, but somehow he succeeds in taking command of the situation. I keep repeating myself: I refuse to enter the bedroom ever again. He tells me I don’t have to.

In the kitchen, a police officer has started going through our medicine cupboard. She asks why we have prescription sleeping pills. I tell her they were prescribed to me so I could sleep after being up with Ivan for so many nights. I ask her to open the packet so she can see that I haven’t taken a single one. It’s important to me that she sees I haven’t taken any. As she opens up the packet, I’m suddenly afraid. What if it’s empty? What if you took your own life? It’s the first time that thought occurs to me. It feels like her fingers move in slow motion. The box is full.

Now my stepmother enters the kitchen. When she embraces me, I start to cry for the first time. As she lifts Ivan out of my arms, I’m at a loss for what to do with my hands. I try to relax and collect my thoughts. It’s impossible. I will never go into that bedroom again, I think. Never, never.

Your mum, dad, big brother and nephew are with us now, as is a doctor, who will examine your body to see when – and why – you died.

Your father breaks down with a howl, a kind of bottomless cry. Completely incomprehensible, he says. I want silence. Your mum is silent. Her eyes aren’t present. Nor are mine.

‘I have no interest in learning to live without you’: Carolina with Aksel. Photograph: courtesy of Carolina Setterwall

Now the doctor is coming out of your bedroom, our bedroom. I don’t want to hear what he has to say. He sits down and speaks slowly. He’s done this many times before. “Carolina, listen, and I’ll tell you what I can about what happened. Aksel died in his sleep late last night, probably just a few hours before you went into the room. I can’t say for sure why he died right now. But Carolina, listen now, he died painlessly. It happened in his sleep. And I want you to understand, Carolina, that it would have made no difference if you were in the room when it happened. But before we move Aksel’s body, I want you to go into the bedroom and say goodbye…”

No. No.

I can’t handle it, I say. I went in when my dad died, and I went in when my grandmother died, but I don’t have the strength now. It’s impossible.

I break down. A stream of snot and saliva flows on to your big brother’s shirt, and he hugs me hard. I disappear into his arms and never want to leave them again. You can do this, he whispers in my ear. We’ll do it together, he says. Let’s do it. This is important.

I don’t know how long we stand there. But somehow, your parents, my stepmother and Ivan have already been in to see you now. They surround us where we stand, circling us in a clumsy hug that almost suffocates me. I can’t get any air, their arms are all around me and I can’t breathe. They tell me it’s OK, that you looked peaceful.

Your big brother holds on tight to me and we go in, together, for one last goodbye. As we step over the threshold, I squeeze my eyes shut.

***

Monday morning. Today it’s been a week. My body commemorated that milestone by finally falling asleep last night. When I woke up, I had no memory of the last few hours. I didn’t remember breastfeeding, nor waking up from Ivan crying, no thoughts and no dreams. That should be a good sign. When I woke up it was five o’clock, and I knew immediately: now it has been a week.

From now on, I’ll count the weeks rather than the days. Weeks will turn into months, and months into years. I will learn that you died of undiagnosed cardiac disease. Somewhere along the way, this existence will begin to feel normal. Someday, each breath will stop hurting, will stop feeling like an effort I’m not sure I’m capable of.

My friends and family have taken over every task they can for me. Together and without much discussion, they’ve become my artificial lungs, heart, legs and arms. They handle all the paperwork, the schedule, the mail. The only thing I have to do is keep breathing and keep trying to make it through these days. And be there for Ivan.

Oblivious to the tragedy that will shape his life, he fills up nappy after nappy. He crawls and stumbles. Cries and then is happy again. Laughs and plays, splashes in the bath and tries out new sounds. Sometimes he even makes me laugh in a way that’s not artificial.

The magnitude of what has happened is starting to sink in. In the books I borrowed from the library about trauma and crisis management, I read all about the stages of grief. It’s hopeful to read about what happens later. I want to get there as quickly as possible. But the books give me little hope that I can move fast.

At the same time, now and then a new feeling arrives. One that will probably become more prominent. A complaining, dissatisfied, whiney voice inside me, that despite all the angels around me, despite all the help and love I receive, wants to tell them thanks but no thanks. After five and a half years with you, I have no interest in learning to live without you. I think I’ll pass.

If you’d just come back, if I could just wake up from this bizarre dream, then I could make everything right again. I promise to never stress you out again. I’ll let you sleep more. I’ll never complain about your pace. You can be whoever you want and need to be. Give me more time, and I’ll do it right.

• Extracted from Let’s Hope For The Best by Carolina Setterwall, published by Bloomsbury at £14,99. To order a copy for £11.99, go to guardianbookshop.com or telephone 0330 333 6846.

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