This is one of the reasons trading is not easy and many lose their money. You need to "train" your mind. I used to read many phycology trading books when I was day trading long ago. You need to learn to lose, even when losing means selling too early.
On top of dealing with your mind, you need to work on a strategy and try to stick to it for a while so you can analyze it and tweak it. Otherwise, all you do is lose money and kill your personal mood.
Trading is not easy, even when you are up x10 some people may tell you you lost 50% because you did not sell on the ATH a few days ago. I do not day trade anymore because I realized my head was not prepared to do it, I invest and swing trade, but I have learned to be patient, think in the future, not the present, and most importantly, be happy whenever your investments are doing good, no matter if they could have been better.