I don't think any actor feels comfortable watching themselves in movies. You must be very narcissistic. The problem with your own opinion of yourself is that contrary to the normal spectators, when you watch a film you are in, you only watch yourself. ↗
Don't give up. There are too many nay-sayers out there who will try to discourage you. Don't listen to them. The only one who can make you give up is yourself. ↗
To the extent that you can find ways where you're making predictions, there's no substitute for testing yourself on real-world situations that you don't know the answer to in advance. ↗
People often remark that I'm pretty lucky. Luck is only important in so far as getting the chance to sell yourself at the right moment. After that, you've got to have talent and know how to use it. ↗