Cramps and back pain

Amber • I`m happily engaged to the love of my life been TTC #1 for almost a year?
So I'm supposed to start af next week and I've noticed all week this week I've been having cramps which isn't normal for me to have a week before but they don't hurt they are just uncomfortable and come and go it's not constant pressure well yesterday I started having some lower back pain and it's usually the top of my back that hurts. Has anyone had this happen cause I just find it weird cause this isn't how my body is ever?