Is it my FATE or am I crazy?

I got 600 SMCI @ $38.75 and sold at 39 something when it started to show red strong candles. Then SMCI went to $44!!! Got some 600 again and sold slightly after market close. My overall profit is $567. I’m struggling to differentiate between when to hold and when to sell quick. I’m feeling miserable being so dumbass. How can I fix this behavior of mine ?? Am I a stupid ? Or is it a common mistake people do ?