How long does breakthrough bleeding caused by antibiotics last? i stopped antibiotics on feb 11 and have been bleeding since feb 11, so for 11 days

I am very skeptical: that breakthrough is caused by antibiotics. Let's say that would be REALLY low on the list. There are 100 better reasons for breakthrough bleeding, but by definition because it's "breakthrough" there's no rule for how long it last. If it persists into your next menstrual cycle check with your doctor; if not, can likely forget it. Good wishes.