I had my period last week which was on time and regular. It ended Friday and over the weekend I got a sinus infection and was prescribed an antibiotic. I began taking it Monday and was told it would make my birth control ineffective so I didn't take the birth control. Yesterday I began bleeding again, only 5 days after my last period. I'm assuming this is because of the antibiotic/ birth control. My question is: is it safe to be having bleeding/cramping so close to my last period and will it stop if I resume the birth control? Or will it be like another full blown period lasting a whole week again?