I'm on progestin-only pill, I normally have rather regular periods. Last month my period came on time but was very light, it came back 12 days after and went for 18 days. On the 8th day it stopped so I had sex and then it came back the next day. If I wasn't on my period then I would have been fertile when I had sex. I'm now experiencing symptoms of pregnancy but I was on my period when I had sex so I can't have ovulated? I also was on track with my pills. Am I stressing out or is this possible?? Going to have pregnancy test tomorrow but this is really playing on my mind and I need opinions?