Sounds like sleep paralysis (eye's closed but not asleep, can't move or speak but completely aware of conversations around you or what is on TV). Should investigate. I suffer from sleep paralysis but also don't sleep well, up many times during the night. Haven't had any problems with the ambien since started about 4 months ago until I had total memory loss 2 nights ago. Totally freaked me out which is why I'm investigating now.
you have something akin to a sleep paraylsis: what is happening is that your body/mind immediately goes into REM although the brain has not been properly sedated for sleep through natural mechanisms. you most probably had this before and for some reason this drug is worsening it. doctors sometimes prescibe TCAntidepressants for this to no avail. i am speaking from experience, but mine has been that these terrifying night-paralysis episodes have abated ever since i took the ambien. im still a student so i dont know all the answers, but what you describe is similar to what i have experienced.
ambien cr memory loss close my eyes i can hear headache depression sleep paralysis sleep well ambien natural mechanisms to no avail paralysis rem brain abated