36 weeks and severe cramping pain!!!

Tonight I woke up needing to go to the bathroom and after I got up off the toilet there was this immediate sharp shooting pain in my lower abdomen. I could barely breathe but slowly walked back and got into bed. I woke my husband with moaning because the pain is so severe! I'm not sure what I should do, could it be the baby moving down? Pelvic pressure and more round ligament pain? I'm a FTM and don't want to go into the ER if it's not signs of labor!