My Periods Are Irregular I Got My Period Last Week

My periods are irregular i got my period last week and had it for 6 days but in between then i had unprotected sex during and in between the time im supposed to ovulate so this SaturdAy comes mind you i have this headache and went in to a migraine lasted all day until i was able to buy tynole. But i had went to the bathroom and noticied i was bleeding. It was a real light pinkish color lasted about 1day and a half. Could this mean pregnancy? I really want to be i just dont want to be disappointed. Sometimes i feel like i should have already been pregnant. How could i tell if im ovulating?