That's the kind of stuff that happens with gambling. Only bet what you're willing to lose. I too lost about £100 last week betting on Leclerc to win an Imola, plus one or two other bets that didn't pay out either.
However, that was just previous winnings. The money never saw my bank account so it was never really lost, practically speaking at least. But obviously, it is lost because it could've been there, but I'm still £150 up from the original £10 bet I made at the start of the season