Bleeding in between periods????

Latasha • PCOS, 4 years infertility, never been pregnant, married, we just started IUI's.

So my period ended last Sunday and it usually only lasts for 7 day because of provera. Well me and my so had sex about 4 times after my period ended. Wasn't rough or painful. Well the day after we did it last I woke up and there was pink? It made no sense because according to glow I was suppose to have ovulation on Friday. I never bleed in between. I felt sick most of the day. Kinda droggy. Just wasn't a good day.

What could cause bleeding??