The Sizing Mistake That Still Haunts My $SPX Trades

Hey everyone, new here and looking forward to learning from you all. I've been trading for about three years now, mostly focusing on options on the $SPX, and also dabbling in $EURUSD on the FX side.

One of the biggest lessons, or rather, a mistake that keeps replaying in my head, involved a pretty significant over-sizing incident early last year. I had a strong conviction on an $SPX call option trade, probably the strongest I'd felt about anything at that point. The setup looked pristine, confluence of indicators, the whole nine yards. Instead of sticking to my usual 1-2% account risk per trade, I got greedy and allocated nearly 10%. Of course, the market decided to do the exact opposite of what I expected, and within a few hours, I was looking at a substantial drawdown. It wasn't account-ending, but it definitely set me back a good few months of grind to recover. The worst part wasn't even the money lost, but the hit to confidence and the lingering fear of over-sizing again, even on solid setups.

It really drilled into me the importance of position sizing and sticking to a predefined risk management plan, no matter how confident you feel. That emotional pull to go big when you 'just know' it's going to work out is a powerful trap. Curious to hear if anyone else has a similar story or strategies they use to combat that urge.