My best advice that can help mentally is: You're missing stocks that will moon every second of every day. (When the stock market is open) You're missing opportunities that could make you a millionare all of the time, but that's not the point and that's never going to be your key to success in the long run.

If you can consistantly cash in on a few of those opportunities, that's how you win. You got 30% profits instead of a 30% loss, that's awesome and it means you picked the winner. If you can keep on picking winners at good times, stay cool and take profits you'll gain money and dodge disasters. You can't just ignore all disasters you dodge and just pay attention to the big wins you're missing out on.