Self doubt and having moments of feeling like an imposter happen to everyone -- and I mean everyone! Think of the most accomplished and successful person you know. Yep, they've felt that way too. It's human nature.
Being that we only have this one, wild and precious life as you and as me, right here and right now, striving to overcome, to lift one's spirits, to find and experience that which is good, satisfying, funny and loving is, for me, the only choice.