I understand that feeling so much!
Thankfully, I teach English as a second language. It is already something that I love, and I will hardly draw the topic too much from it.

The important thing is to always take the subject you are talking about to something where you feel more passionate about. Or at least not make things boring when teaching. It is also important to make students take part in the action.

We have chosen one of the most naive professions in the entire world, and it is passion what makes it work.

Great post!