To me, your hormones sound out of whack and I'm guessing that is what all the bleeding and spotting is. However, you have been off the depo for a good long time and it sounds like ovulation is ramping up. You're still irregular which will make TTC harder. Implantation bleeding is something that you see on the internet but not all that many women really have. Same with ovulation, some women say they spot when they ovulate. Never have known a woman that has done either of those. :>) But if you are actively TTC and had unprotected sex, then yes, you could be pregnant. It's just hard to tell because you don't know first day of last period (as some of this is likely spotting) and you don't know when your period is next due. So, I guess I'd wait until 2.5 weeks after your last sexual intercourse and take a test. That would probably be long enough to get a positive. good luck and let us know how it goes!