Cramps?? Should I be worried?

Leah

Let me start with I'm 30 weeks. And I get really weird cramps like every night now and sometimes just randomly but I get them just under my belly button and in my back. They make me feel pretty sick more then they do really physically hurt me but they still feel painful and uncomfortable. This has been happening for the past week. Anyone know what it is or why I only get it in bed and at night?