Confidence comes not from always being right but from not fearing to be wrong - Peter T. Mcintyre
There is also a saying paranoids survive. The above quote talks about confidence but implicitly also about being paranoid. You should be afraid to be wrong but if you really think, its good to be afraid of being wrong. The only thing you should not be worrying about is what will happen to you if you go wrong. If you go wrong you learn the mistake anyway and all it matters is you don’t make that mistake again. Confidence is all about not only being right but learning from when you went wrong and correcting it the next time.