Could this be early labor? Super scared!!

I’m only 33 weeks but I’ve had cramping in my lower back and lower tummy all day long. It’s constant though so I’m not sure if they’re contractions or not. They’re not very painful but they feel like I’m about to start my period any second. I’ve also had diarrhea for 2 weeks now. Could this mean I’m in early stages of labor? Should I call my doctor or go to the hospital? I don’t wanna overreact but I also don’t want to be in labor right now since I’m only 33 weeks. Anyone have any advice?