Your English is just fine, and I appreciate you asking your question. It’s hard to know why you’ve lost interest, but of all the things you’ve spoken of the “satanic phase” is probably the best place to start. Since you are in college you have access to the college counseling center. I would make an appointment there and talk to a counselor about this transformation in your feelings.
A teacher that invited you to look at life through a different lens doesn’t seem to be a strong enough cause for your reaction. Many other people took that class with the same teacher — and not all of them followed your path. The question becomes what is it that that made you ponder it the way you did? The counseling will provide you with an opportunity for some self reflection and understanding. This can be enormously helpful and you sorting through your next steps.