I Had Urti And Was Being Treated With Amoxicillin 500mg

I had urti and was being treated with amoxicillin 500mg twice a day for 3 days I started suffering with diarrohea, hence I asked to discontinue the drug, now I am taking lizolid 600 since 2 days twice and experiencing vaginal bleeding though my periods got over a week ago, is this due to the drug? This kind of thing never happened before.