Are you waking because of knee pain? It took me about 3 weeks to get back to using my cpap machine after my knee surgery and it was almost like starting from scratch again. I am now at 5 months but I also take 900 mg of Gabapetin at bedtime so it help see sleep as well. I also take Tylenol arthritis right before I go to sleep. I use Diclofenac gel (can't take oral nsaids) and even use Ben Gay 3-4 times a day and if I wake at night use some. Not sure if that's helpful or not. I might ask my Pulmonologist what could possibly help if you think it's just related to your machine.