Was the bat in a room with you or was this outside? Sometimes you can't see a bat bite. But if you were outside and you were near a bat and were awake you would have known it the bat landed on you. Did it? If not there is no exposure. If it didn't come near you and you were awake you would know.
I strongly suggest that you look into mental health counseling. You seem to have irrational fears related to diseases that you cannot have. The problem is not disease, but your irrational fear of disease, and a counselor can help with that.