Pre- menstrual emotions

So my period is supposed to start in 2 days so maybe I'm just being emotional due that... But I woke up and went through fb only to see a guy I had cared about have a gf. About 2 weeks ago an ex reached out only to confirm once again he's still an asshole after I've done nothing Bt be good to him(no worries he's blocked now). Every two weeks I take my daughter to see her dad and I'm reminded of how he cheated and had a son with another woman, found out while I was trying wedding dresses on. I'm a pretty strong woman, I forgive, and I know what I deserve but I can't help but to feel unappreciated. I know I'm good and I know I'm worthy of a good man, but I don't understand why I'm treated like less than dirt. I've never cheated or anything so I wonder why shit happens to me. Even dating has been the worst. Idk, it just take everything in me not to cry and feed into these thoughts and emotions.