question and advice please!!! I'll be thirty weeks Monday with twins, and ever since Thursday, I've…

question and advice please!!! I'll be thirty weeks Monday with twins, and ever since Thursday, I've been getting a pain in my pelvic area. it's not constant. it's just once in a while, usually while I'm standing up or walking and whatnot. it's more like a pressure and it can get painful from the pressure. I go to have another ultrasound Monday!