Running and hip/side pain

I am looking for some help with anyone who has had a similar ptoblem. I am currently 19+3, I ran regularly prior to being pregnant, 3 to 4 times per week 3+ miles. I have been continuing to run since, although at a slower pace and keeping it nearer to 3 miles. Today around mile 2 I felt a burning/ stabbing pain in my lower ab/hip, I walked the last mile thinking it was a cramp and it would go away, but it only strengthened. I have had to lay down all day to let the pain subside. I called my doctors office and they were very confident it is round ligament pain, but to me this is nothing like what I read it to be like, it lasted for hours and i felt like i was going to throw up from thw pain. Either way, baby is good and kicking away, but what can I do to keep this from coming back next time I run? I love to run, and up until now it was one of the few things in my exercise program I could do.