Cramping

So i am about 5 days away from AF. But it seems a little different. I am not bloated like i normally am. I am having some cramps but the lower part of my stomach feels heavy and i have major back pain. Also i know this is TMI but i have had diarrhea for the last few days. An with my son i didnt have anything but the cramping and the missed period. So i am just super confused. I dont know if i should take a test now or wait a few more days.