I can't lose weight...?

Lately, I've been going to the gym, working out more each time. When I first went, I was 128lbs. Now, I'm 130.6lbs. What's going on? Why can't I lose weight? I know it's just a little, but it freaks me out. I'm 14 years old, and I know that some people may say that I'm growing, but usually I stay the same weight for a little while, if I don't work out, and then steadily gain alongside growing.