So uncomfortable

My back hurts like I have kidney stones! I'm constantly drinking water and yet I feel constantly lightheaded and dizzy, and feel like I can't breathe... and my stomach hurts like I have the flu. I have perfect blood pressure. It was 180/60 yesterday at the doctors. I'm. 37 weeks pregnant and I don't know how to feel better. I took Imodium this morning and it helped a little bit. And I've been resting but if I rest I feel worse. But if I walk around I feel like I'm going to faint. Any idea?