EXTREME hip/pelvic pain?

Dr won't openly say I have SPD but I really really think i do. I feel my pelvis grinding as I walk and it's so freaking painful. And my hips are constantly aching. If I've been on my feet for over an hour, it gets to the point where I'll take a step and feel like I will fall. I literally fell down when I sneezed earlier because it felt like my hips were going to snap!! Is there anything I can do to help this?? I'm losing my mind and I still have over a month until I'm due. HELP ME