Early period

I had my period on the 11th of the month, lasted 6 days like usual. Well about 2 or so weeks ago I took off the patch to start ttc, well it said my ovulation time was lastweek my and my boyfriend had sex last Monday until Saturday which was our last day of doing it. Well Saturday we went to dorney and on a lot of rides and the day after (Sunday) I started randomly bleeding and I still am today, I'm a little confused as to why and would just like a few opinions as to why it happened to early. Oh and I'm also watching my diet and taking prenatal pills as well.