Having pain in first trimester.?

How do I know if I am having nerve problems or ectopic pregnancy. It sometimes seems to start near the lower right of my spine and a crampy hot pain seems to travel around the top of right hip and under the front of the hip. Sometimes when I am relaxing its get much worse. Like when I am sleeping. This is the third pregnancy and I lost the other two. I was put on progesterone a week ago. I could be wrong, but it seems like the pain got a little stronger when I started it. This isn't constant pain. It seems like if I move around a bit and maybe take a bathroom break, the pain seems to leave. It doesn't seem to last for than 5 minutes maybe tops.