trouble sleeping on my sides.....

I am 22 weeks now. The past few days I have had trouble sleeping on either side. My leg at my hips (which ever side I'm on) tends to go somewhat numb. This wakes me up as I am uncomfortable. The solution I've found at the moment seems to be sleeping on my side/stomach. I haven't had this trouble before. Anyone else have a similar situation? I go to the doctor again in 2 weeks. Figured I would try and wait u till then to mention it.