I agree with zheer, but it seems the things you're worried about have to do with performance anxiety. After all, you wouldn't really be doubting yourself if you weren't performing, would you?
Solution: Practice performing. You have family and friends, and now they are your guinea pigs. People may think it's showing off, but that doesn't matter. When a piece is ready, and sometimes even before, you need to start sharing it with people. Everyone. They say you can't really perform a piece to the best of your abilities until you've performed it at least three times. It's great to practice theory, movements, interpretation, whatever, but you must also practice performing if you want to get good at it.