Just wondering if anyone else has had this problem and if it could be related to sleep apnea or CPAP... Since about February I've been waking up about 30-45 minutes after falling asleep (no problem falling asleep) and it's a sudden waking up with a feeling like something is wrong but nothing really is. I have no pain, no symptoms whatsoever except sometimes I'm shaky, I'm guessing from waking up so suddenly. My CPAP machine seems to be running okay, no obstructions etc. Sometimes I have trouble falling back to sleep but sometimes I'm so tired I'm not awake very long. It's driving me crazy! I've slept so wonderfully in the 2 years I've been using CPAP until now. When this first started happening to me, I started getting anxiety about going to sleep but then I guess I got used to it but it's still bothering me. If something is wrong, I need to fix it!