Are you familiar with
the gambler's fallacy? That's exactly what you're engaging in with this kind of thinking. The market doesn't know that you made 20%, or 3%, or whatever; it doesn't know, and it doesn't care. If you have a trading edge and do the right thing, you'll win over time; if you don't, you'll lose. Superstitious nonsense like "I won, but if I keep trading, I'll lose it all!" is a loser belief; it has nothing to do with reality.
If you start overtrading or taking inappropriate risks, that's got nothing to do with your P&L; it's just you deciding to overtrade or take inappropriate risks - so you shouldn't do that. If you get overexcited due to your winnings and need to calm down, then take the time to calm down.
But if your edge is specific to the current state of the market - and since no trading system is perfect for all types of market, it's not an unlikely situation - then it would be stupid to stop trading, because your system is working
now, and may not work later (when the market changes again.)