The class you failed probably taught you more about yourself than the one you aced.

Success is quiet about its causes, because when things go well nobody examines anything. Failing hands you a detailed report on how you work: what you avoid, when you stop, what you say to yourself at the point it gets hard. That is uncomfortable information and it is also the useful kind.

Go back to something that went badly and ask what it showed about your habits rather than your ability. Choose one item from that list to do differently. The result is gone, but the pattern is still running.