Alamak, 30 weeks memang ada macam ni, perut dah besar, pinggang sakit, susah cari position yang selesa, I feel you! A few of my mum friends kata around this time they were waking up every 2-3 hours, restless je, and one swore by putting pillows between the knees and under the belly to support the weight better. Try sleeping on your left side, it's supposed to help with circulation and make baby comfier too. Definitely worth a chat with your doctor about the back pain though, just to make sure nothing else is going on, they might suggest physio or safe stretches lah. You're doing great, mama, this phase will pass!