Hi, guys. So, I sleep with my air conditioner turned on and I've noticed that sometimes when I go to sleep, I realize that I can no longer hear the noise of the AC and find it strange. Then, I get surprised by that and kind of wake myself up to start hearing it again.

Can someone please tell me what this means?? Is it that the times when I'm not hearing my AC I'm actually mentally aware but physically asleep? If so, can someone tell me how I can keep that state of awareness and not wake myself up physically? I look forward to your responses. Please and thank you.

-Ajanime22