36 week cramps

Aside from the dull ache in my groin and crotch area, I am now getting what feel like menstrual cramps in my lower pelvic region. The cramping has actually woken me up the last two nights, but so has the need to pee at the same time.

So my question is, what is this?  Is my uterus preparing or doing something else? I have nothing else happening, baby is in the right position and has been for a while now. No mucus plug, no idea if I am dilating or effacing. No bloody show or leaking fluid.  I think I may have dropped, but I have carried low the whole time, so I have no idea. Anyone else?? Thanks for input- I figure if it becomes more instance and regular I'll call the OB.