I had a similar problem where I would be cold before I fell asleep so I bundled up and was warm and fell asleep easy, then I would wake up sometimes sweating because I had added too much insulation to warm up so I could fall asleep again. I would definitely try sleeping in a base layer or something similar so that you have a little more insulation directly around your body. That way your core temperature will stay a little more constant and be less effected by changes in the weather (wind, temps, etc.)

Also do you use a tent, tarp, bivy, or what when your backpacking? If your in a tent the microclimate should be a little more consistent than if you're using a tarp or sleeping under the stars.