This has been answered nicely by everyone.
Jathaan's answer really resonates with me, thumbs-up. And Matty, too - thumbs-up.
I think all of us (ahem...) serious artist-types experience this to some extent. I had a class where virtually everything I did - and I mean really off-the-wall, personal, unique stuff - was lifted by my classmates.
It's really your ego that's bugging you. Don't worry - when you have original ideas and solid technical skills, the amateurs will always be miles behind you.
Don't worry about what they're doing, just go deep with your own vision, expression, searching for meaning, taking creative risks.
There's a point were you will *own* your tech skills - in fact, you'll probably have too much technique and may start over-working your pieces. Then you'll make this mental leap into meaning, content, expression, risk. You'll start getting really loose, un-learning all the dogma of art school drawing classes. The tech chops are just the tools you use to realize your vision. It's like the way vocabulary and grammar are used to communicate ideas and concepts.
Pure technique with no meaning is pointless in fine art. Nobody's impressed by pure technique when you get to MFA and gallery-land, trust me. You're just going through the technique phase - and the competitive, ego phase - and you're already realizing that. As Matty said, it's not a competition. It's what you have to express that is most important.