2nd time mom's, cramping?

Rinny22

I am 15-16 weeks with my second pregnancy and have been having consistent on and off cramping, like menstral cramps.  I called my Dr. because I don't remember experiencing this in my 2nd tri with my DS .  She said that cramping was normal and that subsequent pregnancies can have more intense cramping. 

 I'm still worried about it.  I feel like I should push to go in for them to check the heartbeat, but I don't want to overreact either.  Has anyone else experienced this and had a continued healthy pregnancy?