I have an obsession with my teacher
What made you obsessed with him?
It's because we share common passions and we may grow closer as we share more interests
Wanting to be closer to people who you share somethings is normal but it is not good to obsesses so much that you don't care about nothing else. It is good to seek help to deal with your obsession.
I just want to enjoy my time with him.
It just really sounds like you are a bit obsessed with this person, which is unhealthy. You should try and find someone that you like that is your own age.