Had a period back in June missed July and don't look like I'll be having a period a period this month either(august). Yes I had been having unprotected sex (May-july). So this past weekend my lower back was hurting like I'm about to start my period, when I'm about to start I have lower pains. So Monday when I went to the bathroom and after wiping I looked at the tissue and it was very light blood on the tissue(sorry for tmi). And that was it, haven't bleed since and my back doesn't hurt anymore. I still feel the same just be bit more sleepy than normal and slight cramping In my abdomen.