I've never been a brilliant sleeper, but since my darling husband Leo died last November I've only managed to grab three or four hours' sleep most nights. Losing him was such an overwhelming thing to happen, and now, without him, I feel like I have such a very big bed. Of course I miss him terribly, but I am doing OK. I wouldn't want people to think I wasn't.

Luckily my beloved greyhounds are keen to fill the bed space. They're always rushing into the bedroom through the night to try to clamber on to the bed first. There follows a stand-off when one of them manages it, as the others then won't climb on. While the dogs often whine, which can be annoying, it's nice to have someone to talk to.

I live in Gloucestershire, where there's little light pollution, and when I can't sleep I love to look up at the stars. I'm a keen astronomer now and know the stars very well. The night Leo died, I looked out and saw the constellation Leo was rising in the sky.

Sometimes I go to bed at midnight, then wake at 1am. I might go back to sleep about 5.30am then wake up at 7am. There's never a reason I can put my finger on, but it's most frustrating. It's very easy to fill the hours, though. I'm in the middle of a novel about racing at the moment, so often read back over what I have written and change bits around or fix little things. I also read the Racing Post, which is a fabulous paper and has terrific story ideas in it. Sometimes I do the crossword, but the other main thing I use the night hours for is my correspondence. I make sure I write back to everyone who writes to me. I feel terrible if I don't. Personal notes are written back in longhand, but most others are dictated into a tape recorder, then my assistant types them up when she gets in in the morning.

I have tried so many things to make sleeping easier. When I was younger I used to pinch half a Mogadon if I went to parties or somewhere, but now I am prescribed zopiclone. I take just a nibble of it – literally a 12th of a tablet – as it makes one feel very fuzzy in the morning. I've also got a wonderful Cotswold Lavender Slumber Spray and a White Lavender Pillow Mist from the White Company.

The most important thing, I find, is not to start worrying about not sleeping. I can't allow myself to start becoming concerned about getting work, or paying my tax bill or becoming slow with my writing. It's important just to be constructive. The only time it does affect me is if I have to go somewhere in the morning. I don't want to have huge bags under my eyes. The only thing worse than not sleeping is rereading something I have written in the day and it making me go to sleep. If that happens, it's a very bad sign indeed.