Help?!

I have pcos but I have regular periods not sure about O, but my last period was on 2/18, we BD (baby dance (sex)) multiple times on 3/5-3/6. (3/5. Being my supposed O (ovulation)date) not thinking about that we DTD. Now about 8 days away from my period, yesterday I had VERY light deep red-brown spotting along with some mild cramps. I put a tampon in, and had it in almost all day and when I took it out it was clean. I keep checking and I'm not getting anything when I wipe not and nor am I getting anymore cramps. Im not sure what to think. So my question is, could it have been IB?