A fool and his money . . .

It's the biggest cliché in gambling. And after my behaviour on Thursday, I must be the biggest fool on the planet.

Boredom at work led me on to Betfair. I was keeping my head above water, when the inevitable happened. I laid a big-priced horse for the sake of winning about £4 and, after it had surpassed all its known form, I had lost almost £100 on a horse for the second time in 48 hours.

I had written on here at the time that I must stop taking bets on horses I know nothing about in races that I can't watch. Yet I've done it again – and lost big again.

I am starting to worry on many fronts. Not only about my bank balance, but also about my sanity. Even more worryingly, I am worried about being addicted. I eschewed a night out to go home to try to retrieve some of my losses on the evening racing. I had a good night. I recouped £50 – and if it hadn't been for a losing bet that went to a photo finish, it would have been £90.

The following evening, I made another £30. So I had wiped out all but £20 of the deficit. But if I had shown a little more discipline, I would have been about £600 up over the past seven days.

Running total: you do the maths