unsure what this crampy pain is

Leah
So I've been waking up the last couple of nights as I turn over to a really horrible painful very low down cramping, I can't figure out if I should be worried about an infection or if it's just where baby boy is lying so close to my cervix when I sleep maybe? As I've Been told he's very low down still. What do you think? It doesn't hurt in the day only at night