Have you tried the exercises/tasks that you did with your class teacher but riding switch instead? Sometimes people try to jump straight into learning switch by mimicing what they currently can do in their regular forward stance. Breaking it down to simpler tasks like a straight traverse, j-turns, garlans, etc. can help. Also the size of the turn attempting can make a difference.
Also to help you out better more detail to what happens when you try to ride switch helps. i.e. when do you fall toe to heel, or heel to toe? Do you fall down the hill or up the hill? etc...
When I was in a class, I did ask to ride switch, but I'll notice the rest of those things.