Hi Azariah,
It's often been said that confidence builds confidence, and I really think it's true. There comes a point where you have to just put aside the doubts and try and throw yourself into something. Many people in life, myself included, can hardly believe that someone could love them, or that they could achieve the things in their career that they have, and so on. And yet these things happen for people.
It takes a first step of courage to get going and find your sense of self worth, I spent many years idle thinking I could never get a decent job or that I had three million things wrong with me. It was a complete waste of time and I wish I'd thrown the self doubt out of the window a lot earlier.
Wishing you all the best, please remember to punch the gremlin of self doubt in the face next time it pops up.