Just because you go to church does not mean you are a chiristian and just because you confess still does not make you christian.
What makes you a christian is according to bible. To actully have been saved you have to believe in your heart that Jesus is Lord, and confess with your mouth that God raised him from the dead, then you will be saved.
You came here because the holy spirit troubled you. If you are having doubts you are most likely helping those students cheat.
What if one day you became very ill and need a lifesaving operation. And you find out that the person who is going to operate on you is one of your students who you know would have failed if it was not for you, how confident would you be with that person operating on you?
I will be praying for you brother.
If you are worried about not being able to provide for your family think about this, why don't you get rid of the part where you totaly write the papers and instead become a person the reads and grades the students papers and sends them suggestions and edits.