Why do I get board with my looks?

I was more confident but I'm getting board with my looks and looking at myself. I know Iam a guy and shouldn't worry to much about this but why am I so less confident with myself. My mom says it's because I have a pimple problem lol but I just got a haircut that this model had and I ended up looking good just like him but than the next day it was just normal. I mean it looked good and clean but no matter what I do I can't live up to my expectations like I've been on a diet this past three days but all I've really eatin or drink was welches 100% g juice and peas. Why cant I just be happy with myself all the time and why do I feel so unsecure.