Reaching out to ex

So every single month right before and during my period I start missing and wanting to talk to my ex. Pretty much the rest of the time I’m 100% okay not talking to him but idk if it’s all the hormones or what, but I just want to talk to him around this time. It’s getting harder and harder to not reach out to him and it’s so frustrating because I just want to finally be okay all the time while not talking to him.

I mostly just miss his friendship, we were together for five years and it’s hard not having that person anymore at all.

I don’t know what to do.