Spotting

Hi ladies! Glow says my O day was 11/19. We made sure to have sex all throughout my fertile window and even the 2 days following my O day. 3 days ago I had the weirdest pain in my left side and also in my back. Lasted maybe 10 minutes. Yesterday evening after going to the bathroom, I had reddish orange spotting when I wiped. It wasn’t a lot. Then I had it again this morning but not a lot. Glow says AF is due Sunday but I am thinking more like Tuesday based on the lengths my cycles have been. Any suggestions on what this could be? Or has anyone experienced anything similar?

Thanks!