This is a very common difficulty. You may find it easier to roll over on a firm mattress. If you think your mattress is too soft place a board under the mattress to support it.
Here are some hings to help you roll over, in this case to your right side. Reverse the directions to turn to your left side.
- Band your knees and put your feet flat on the bed. Swing your knees to the right side.
- Grip your hands and lift them up straightening your elbows as you do so.
- Turn your head and swing your arms to the right. You may need to repeat this step several times until you have rolled over sufficiently to grip the edge of the mattress to pull yourself over further if necessary. Adjust your position until you are comfortable.