Could I be pregnant?

[2009jormc]

All little back ground info-- my cycles are irregular but just somewhere around 35 days.  If it was the same this month, I had unprotected sex on the day I should have ovulated. An exact week later my period started but according to my calender if it was a 35 day cycle, I was 9 days early.  I usually know when I'm about to start my face breaks out, I have one good cry about something dumb but this time I didn't even realize I was starting, thought I still had at least a week. My "period" last 3 days, started out light got moderate for about a day and then light again... I'm just wondering if this was in my period or if it could have been implantation possibly.