Ovulation or Period?

I have PCOS and my cycles are VERY irregular. I am taking Metformin 1500mg daily. Today is cycle day 24 for me and according to my OPK, I should be ovulating today (I had a positive OPK test yesterday). However, since late last night/early morning I’ve been experiencing light cramps and “fullness or heaviness” in my uterus. Slight lower back pain. Also kind of bloated. Sorta how I feel when my period is coming. Unsure if this is ovulation symptoms or if my period is really coming? Has anyone else felt like this or something similar? All replies are appreciated!!!