Hi!
That's why you have to know your average strike rate and also your strike rate on any track you usually bet.
That way you can follow the trend, and if your system, or your form selections are consistent you can even vary your bets accordingly. Ie. let's say you know your ave. strikerate is 20% and you are way above, then it is likely, mind you only LIKELY that your winning streak is not going to last long. But of course you must have had enough races and bets in your records to make it meaningful.
I personally stop when ahead, but I do bet a reasonable amount, so ahead means a couple hundred.
Cheers.