The profit turned into a loss

Today, Hong Kong stocks plummeted again, and many stocks were washed in blood. Some stocks rose at the beginning and were bought yesterday. $AVICHINA(02357.HK)$It rose more than 5% shortly after opening, but closed down 3.66%. In fact, I had a lot of time to sell it at a profit, but it turned out to be a stop-loss sale in the end.
Sometimes I would advise other shareholders not to turn profits into losses, and I was actually repeating this low-level mistake.