Try a heat pad on your back and massage your legs the best you can or get someone that will do it for you. That helps me. I'm 38 weeks and a few weeks ago was when I really started having back pain more. I found sleeping at that time was almost non existent and it seemed to make my legs even more restless, so try to get some sleep whenever you can or at least get your feet up when possible, it'll take the pressure off your legs and back.
Good luck hun :-)
I would call the doc to be safe, but sounds pretty normal.