Stomach quivers?

Okay, so I'm 26w2d and this has been going on for about a week. I don't remember it happening with my first (and only) pregnancy and it's starting to freak me out a little! Every now and then my little girl feels like she's having a seizure or shaking or something! My stomach like... Starts spasming for a few seconds/minutes at a time. Sometimes it's low, sometimes it's belly button area. Has this happened with anyone else? Is it just normal baby movements or should I be concerned? I'm high risk so anything out of the ordinary freeeeaks me out.