We all have doubts about ourselves. If we didn't we'd all be dicks like Trump.
Doubt isn't a bad thing in and of itself. But it shouldn't hang around. Don't feed it.
Look it in the eye, evaluate it with a clear head, learn what you can from it, and then discard it. Doubt is a reminder to look inward from time to time, and make sure you are who you think you are.
Doubt is a fortune cookie fortune: Interesting in the moment, but useless in the long run.
(And by the by... the "sad panda" visual that appeared in my head almost made me spit out my coffee, it was so funny! Thank you for that!)