I am confused:((

hi my dear colleagues!!
I want to state one of my problem about being a teacher:( Our mentor teacher tries to be beneficial for us as possible as she can be. On Wednesday, she gave us some assignments of the students in order to check them. She explained how we should check them; what the criteria we should consider into, which symbols we should use to show the wrong things, etc. All these are fine..While checking the assignments in the evening, I feel like a real teacher who studied at her home also. This is my problem:( I feel the burden on the teachers that their work does not finish in the school, but goes on at their home and in their free times. So I feel a bit depressed and already bored with my future occupation. I really wonder whether you have this kind of negative feelings about being a teacher or not.. Am I the only one who depressed about her future job at the very beginning of it?!!