To add to what izzy said - you are putting all your feeling 'eggs' into one basket. Your life is revolving around this one person, and that's not healthy. Even those of us who are in love where it's reciprocated tend to have lives outside of the relationship.
Mooning over your teacher means you're not taking risks (not bad risks, I mean relationship risks) with your peers. I am also troubled by you saying you have entertained suicidal feelings. This is off the charts and has gone beyond a crush.
I would suggest counseling as you are going to end up having a devil of a time adjusting to the world when you graduate.