It's the last four weeks of my training.
I am averaging more than 25 miles a week, sprinting and lunging and popping push-ups and running for upwards of three hours every Saturday morning.
It's been 12 weeks since I started preparing for the London Marathon 2014. The rain has eased. The mornings are bright. The evenings, though still dark, are less cold.
The anticipation is building.
I should be feeling like an athlete, toned and ready.
Instead I am knackered, and sore.
I don't feel like an athlete. I feel like an old car, being driven at faster and faster speeds until everything is vibrating, and nuts and bolts loosen and ping off. Any minute now the windscreen wipers will start to flip crazily of their own accord.
I so hoped this time my final preparations would be happy. The signs were good - the easy 14-mile run that was an almost religious experience; the 5k sprint I did in 26 minutes. I thought that this time I'd cracked it - the training, not my poor old bones. I thought I would fly through my last training runs of 17, 18 and 20 miles.
I did not think I would not be repeating my experience of 2012 when I spent the last four weeks pre-marathon mostly on the osteopath's table.
This afternoon, I'm off to the osteopath's table.
Saturday's run started off so well. I succeeded in getting nearly accidentally-on-purpose lost, essential when undertaking runs of this length. Doing laps for 180 minutes would test my sanity more than my legs. However, getting totally lost would risk running up some rotten hills, given my local geography. I have to find a happy medium of nearly not knowing where I am - sufficiently distracted by my surroundings to clock up the miles enjoyably, while still able to run home via routes somewhere close to sea level.
The first hour was fine. The next five minutes was fine. The next five minutes revealed a niggle. The five minutes after that involved a lot of pain. The shock of it was followed by plummeting despair. I kept running, but headed for home. I paused my stopwatch, and stood in the hallway, trying not to cry and wondering what to do.
"I don't know what to do," I said to my husband, and started crying.
"What do you want to do?" he asked me carefully.
I knew what I wanted to do. I turned around, and went back out, and started running again.
The pain felt familiar. It felt like the pain from last time. It started in the right side of my lower back, then probed into my hip and groin and progressed remorselessly down into the side of my knee.
I ate energy bars and wiped tears away and kept going. I turned on my ipod. I turned it up loud. For a short while, I managed to push the pain into the background. I got to a very doggy bit of the local park and was distracted as ever by dodging the terriers. This time, it helped.
Amazingly, and wonderfully, I got a second wind at 13 miles, when I realised that I'd matched my second-best half-marathon time. This is not a fast time. Don't get excited. But I got excited, and that helped too, for a while.
Fifteen miles was grim. Sixteen miles was grimmer. During the seventeenth mile the pain was like sparks inside my head.
I finished, and walked home on legs that felt like glass. I went on Facebook and made a joke of how bad it had been. Then I sat in the bath, and wondered what to do next.
This afternoon, I find out what to do next. My osteo appointment is in a couple of hours. I still hurt.
In the meantime, I'm watching my Twitter feed - full of fast, hearty runners whooping with joy at doing 20 miles faster than last week. I feel like Ebeneezer Scrooge. Where are the people who had a crap run? Where are the people who hated every minute of the last hour and could barely make it up the stairs afterwards? Surely I can't be alone?
Don't get me wrong. I'm not sad not to be fast. I have always been a plodder - out and proud. My marathons are as much about raising money as raising mileage. I ran my last (first) London Marathon for my daughter, who has Asperger's Syndrome, and for the wonderful National Autistic Society, who supported us throughout the long, painful process of diagnosis and finding support. I thought I should run another one for other people's daughters, and sons, who have autism, and need more support than they're getting. My ambition in running this marathon this time is to raise squillions (or at least several thousands) for Ambitious About Autism, which believes children with autism should thrive, and achieve.
I won't ever clock a time under four and a half hours, and I'm ok with that. I salute all of you who run like whippets. Of course I'm envious. But I'm also realistic.
It's just that I hoped this time wouldn't hurt quite so much.
While I wait for my appointment I'm taking painkillers. But I've realised that the best anaesthetic is this one, right here. It's what ensures that whatever else may happen between now and April 13, I will get around the course and across the finish line. Even if the doors fall off.