Cramping/contractions only when standing?

Shelby
Has anyone ever experienced cramping/contractions only while standing? For the last two days I've had cramps and contractions that start in my belly and the wrap around my back all the way to the front of my belly again. But I'm only really experiencing them when I stand at all.
They make me feel lightheaded and like I've just done an intense work out.
Has anyone else experienced this? I'm 38+2.