10 wks pregnant, pelvic floor achiness?

I am 10 weeks into my pregnancy. The past three days or so, my pelvic floor has been really achy. I had this a lot with my second child, and each time I had gone in to have it looked at, my cervix had thinned out and I was put on bed rest and in the hospital for days at a time. So, I'm really very concerned about it now, especially being that it is SO EARLY in this pregnancy.

I called my OB and she said to rest the weekend and if it isn't better to make an appointment next week. But, I'm pretty concerned, especially with all the trouble I had last pregnancy. I didn't have this kind of issues until I was 30 weeks along.

What could it be, and do I need be as worried and concerned as I am??

Thanks alot!