It’s OK to drop a class. You won’t be the first to do so, and still apply to medical schools.
At this point, you need a major you love, that you can do well in, and that you feel confident about. Find that.
I think I suggested a while ago that you put medical school (and now dental school) on the back burner for now.
@WayOutWestMom are the required courses for medical school applicants the same as for dental school applicants?