So me and my boyfriend are trying to conceive and have had sex everyday the week I ovulated. Ive been having heartburn everyday, feeling very tired & bloated, having headaches & dizzy spells. I usually have very regular periods (28 days) but the last 3 months have been 21-25 days long. I got what I think was my period on September 17 even though I wasn't supposed to get it until September 24. It started light & got a little heavier & lasted 3 days with no cramping at all. Now the bleeding has stopped, I'm starting to have mild cramps with no bleading. What could this be? Could I possibly be pregnant?

You had sex... yes you could possibly be pregnant.
Take a pregnancy test perhaps?

You had sex...yes you could possibly be pregnant.
Take a pregnancy test perhaps??

Do you think that was implantation bleeding or just my period coming early?

What we "think" is just a guess. And it would be foolish to guess. Take a hpt (wait a couple of weeks to do so) or see your doctor.