4 weeks pregnant BAD pain

I’ve has two children and never had this much pain this early in my pregnancy. When I get between 30-40 weeks I get really hot and uncomfortable and if I’m up doing things I start getting bad cramps in my lower back and stomach. The only way to get rid of it is to lay down. Well I literally just found out I’m pregnant a few days ago and I’m only 4 weeks and I’m feeling that super uncomfortable and sharp pain. Feels like back contractions. Anyone know what this could mean??