The transition between up and down is the worst bit, or down and up. You don't realise how much you need the muscles until you don't have them.
Once I am lying down I am OK flat on my back or on my right side with a pillow between my knees. Moving between the two is agony. This makes sleeping a series of 2 hour bits interrupted with 10 minutes pain. At least I am getting some sleep.
Really feel like getting up and getting going, but my body is telling me to lay here as getting up will hurt. Just had two horse size paracetomol and once they kick in I am getting up.