Funny you should mention this, because I've been having the same problem...but on the other side. I keep waking up on my tummy, which has been worrying me. All the different midwives I've spoken with, or read their advice, say that one can sleep in whichever position is comfortable for you. Your body will tell you if the way you are laying is bad, either you will get short of breath or your legs will fall asleep, or your back will ache, etc... Otherwise, they all agree that sleep is precious and enjoy it however and whenever you can! If you feel uncomfortable however you are positioned, then move. Everyone seemed surprised that I could still get onto my tummy, but told me that if the baby and I could sleep that way, then pleasant dreams.
Use pillows to create yourself a big nest, prop up areas that need support and make yourself more comfy. I have a big body pillow that I use and it really helps keep me comfortable. Some people like lots of little pillows, they find them more adjustable. Hope you find something that works.