Sounds like your scope is too far back.
Is your right leg pulled up, so you are leaning on your left side?
You are using a sling, correct?
Practice the position as you watch TV, from the floor, head up.
When I shot a lot of prone, I looked forward to getting in position (NRA Highpower matches). It was very relaxing and comfortable.
Good
video - would be better with a sling.