A Tad Frustrated

So as most of you know I absolutely love to play the piano. I have played since I was eight years old. I have always enjoyed practicing, learning new songs, and sharing my talent with others. Lately though, that does not seem to be the case. For about three years now I have been stuck in a rut when it comes to practicing. I want to move forward because the level I am at is too easy, but when I start to play harder pieces I get super frustrated, really down on myself, and I don't want to play anymore. I really haven't had a problem playing in front of crowds, but since being at a standstill, I get extremely nervous no matter how long and hard I have practiced. It's so irritating! With the way I have to stick to a strict class schedule now, I can no longer take piano lessons anymore. They told me it is not required so I shouldn't keep taking it. Boo. I WANT to sooooo badly! However, they wouldn't let my petition go through when I put the class on there. Now it's going to be even harder to get my butt out of the apartment and find a room to practice in.
Sigh, I'm usually not one to complain like this but when I have felt like this for over three years, it kind of eats away at you. I don't want to lose this talent that I have always enjoyed. Call it a bit dramatic but if I do, I will lose a piece of myself. What to do???