You sound like a talented, bright young woman. I encourage you to continue pursuing your passions, be they music, writing, or other interests.
A Normal Crush
What you've got going with your Theater Arts teacher is a perfectly normal high school crush. You need to differentiate, however, between (justifiably) wanting your teacher's attention for the good work you do in class and (unreasonably) expecting his personal romantic attention.
He Could Be Your Mentor
The situation you describe is delicate, but I believe there's great potential here for a positive, enriching mentor-student relationship.
You should ask to speak to him outside of class, and tell him that while you find him easy to relate to, you're feeling slightly neglected in his class. My suspicion is that he pays as much attention to you as to most of his students, but that you'd like more, so it seems like less.
Let Him Be Teacher, Guide, Mentor
You could tell him about your interests and ask if he's into the same things, and if he could offer advice about these areas (music, acting, etc.) -- let him take the role of teacher, guide, mentor. You may find a new friend, as well, but you'll at least gain some insight into his personality.
Guys Your Age
In the meantime, look around -- I'm sure there's some decent guys around your age walking around... Enjoy your youth -- it'll be gone before you know it!