Can being ill and antibiotics effect my period?

i have had bronchitis for 6 weeks, i was on no medication for this. i finally got over this and a few days later i got a tooth abcess and was on antibiotics for 5 days. My period was due a few days later. It eventually was 4 days late! i am 30 and normally like clockwork every month. It seemed to start like a normal period but only lasted for 2 days with very light spotting for the 3rd day! i am normally no less than 5 days. I do not think i am pregnant as i have no symptoms apart from my growing a cup size but no tenderness or nothing that would be expected with pregnancy. I did do a pregnancy test a week before my period was due as i was very teary and emotional,(not like me at all) and thought i'd do it to be on the safe side and it was neg. Can antibiotics affect my period in this way?? thanks a mill xxx