Ovulating so soon

So my SO and I had unprotected sex 8 days ago..and again 4 days ago. I just got off my period 2 days prior to that and now I'm having very very light brown spotting, this never happens to me. My cycles are 23-25 days.. I think I'm ovulating right after my period, and I'm curious if this could be implantation bleeding... I've also had small cramps on my right side. Has this happened to anyone else and turn out to be pregnant?