Feeling uncomfortable around someone you have a crush on isn't all that unusual. It can be difficult to feel so strongly about someone who may or may not feel the same way about you.

Your feelings of weirdness about the situation are probably only amplified by the fact that you'll (hopefully) never find out if your teacher feels the same way about you--it is not only a conflict of interest, but it's also against the law for teachers and students below the age of 18 to have a sexual relationship.

Understanding what your feelings are and why is one way of helping you to feel less nervous and odd around this teacher. It's also helpful to remember that most "authority figure" crushes are harmless...so long as they remain crushes. There's no harm in thinking that your teacher is cute, hot, fun, charming, whatever. In fact, seeing something that you admire in an older mentor can be pretty valuable and help you figure out what you want in a real-life, legal relationship.

Finally, remember that everybody feels this way at some point in time-- knowing this might make you feel less freaked out by the whole thing.