Braxton Hicks at 20 weeks

So this is my second pregnancy and I am 20 weeks. I had them with my first child but definitely as bad as I am having them now and it has been going on for hours. I can feel the baby moving and kicking and I swear a foot is trying to break through my vagina (sorry TMI) but that's exactly how it feels.
I am dealing out because my daughter was a preemie and I am petrified that this one will be early than my daughter was. Anyone else have this happening???