Welcome to the forum! I agree with what Gwen and wombing have suggested above - you're experiencing sleep paralysis. Wow, I bet you're glad you're not crazy!

Seriously, everyone has sleep paralysis - it's the body's way of keeping your body from acting out your dreams. Sometimes when you wake up, your body is still in this state. No worries, stay calm and it passes. I'm surprised your doctors didn't suspect this.