I don't really think about withdrawal very much except in connection with a) my horrific overdraft b) nicotine and c) heroin. I don't do heroin. I'm not Socttish enough. I gave up chocolate for Lent when I was 16 and was so upset after two hours of the prospect of 30 days without it that I ate three Snickers.

Nobody likes withdrawal because it reminds us that we need stuff and that's wholly at odds with the idea of being free-thinking and choosing our own path down the yellow brick road. At the moment, I'm stuck slap-bang in the middle of chemical withdrawal and it fucking sucks. Rather than writing Trainspotting via Clapham ("We've run out of organic limes!") I would just like to warn you about something you probably know about already, being more interested in life/medicine/stuff that happens outside of fiction than me.

It's called Seroxat and it fucking sucks. Before I found this out, I thought it was called Paroxetine which it is, to give it its less glamorous Tesco's Value equivalent name. The three evils of job hunting, panicking about losing any grip on writing I'd made in the last two years and whether anyone would ever employ me for longer than 9 months made me even more anxious than usual, and given my brain had a tendency to self-destruct until three years ago, my doctor went all American and thrust pills at me, ones that incidentally have the highest incidence rate and severity of withdrawal of any similar pill. Like, score!

On Friday, after a month of numbness, yawning and general meh, the pills ran out. Yesterday I burst into tears within ten minutes of getting out of bed and didn't stop for 8 hours. I wrote a furious and outraged email to a friend that was way over the top however annoyed I was, and I haven't bothered checking my inbox to find her inevitably furious and outraged reply. My boyfriend thought he'd done something wrong, but nobody had – it was just my brain suddenly realising it wasn't being zapped into numbness by suicide-enhancing anti-anxiety tablets and throwing a massive wobbler in the process.

Today I just feel sick. The sort of sick where you can't see any way of getting through it because you're about to cry anyway. Everything is misted up in a grey veil of panic and upset, about absolutely nothing, about tears and the fact my head is being denied this horrendous drug. I've taken it for a month for fuck's sake, this is utterly absurd. There's a reason people go on this for so long: coming off it is exactly that – coming off. Ironic when none of the myriad tablets I was prescribed when I was actually ill did anything other than give me something to do every morning.

I absconded to BDQ headquarters in Windsor last night and for a blissful 12 hours felt safe and happy. Then I got the train home this morning and hid behind the Style section of the Sunday Times quaking in a hot puddle of saline surrounded by burly men and yummy mummies in Wasps shirts.

Depression isn't my illness anymore and hasn't been for years. I'm no happier or sadder than anyone else in London. What I am is at the mercy of my body, and it absolutely sucks. Screw Seroxat, Paroxetine, and doctors who'll throw drugs at anything that moves because the NHS gives them sod all support to do otherwise. Don't take this drug. Don't let anyone give it to you. Eat coconut and lemon meringue ice creams instead. And smile lovingly at your Pirates 3 screening ticket for tomorrow evening. Aces.