Sleep patterns

At the beginning of this semester, I made the decision that I was going to try to get into a sleeping routine. I've never had sleeping issues, which I am so grateful for and know I am incredibly lucky, but I also knew that my inconsistent sleep patterns would probably catch up with me eventually. Thus, a sleeping routine was created. I try to sleep from 12-8. Some days are more successful than others, but I usually do a pretty good job of keeping it in a 30 minute window of my designated times. Anyway, the last few nights, I have been waking up around 6:30. It doesn't keep me up; I just roll over and go back to sleep (again, I know I am incredibly lucky that I can do this). It's quite odd, though, and a little confusing.

The only thing I can think of is that one of my REM cycles ends around six or six and a half hours into my sleep, and for whatever reason, my body isn't transitioning well from REM sleep back into NREM that particular time. Either that, or somebody in a neighboring apartment has an alarm clock that goes off around that time that is causing me to wake up. There's also my best friend's explanation, which is that I am a grandma. Not in the literal sense, of course, but I do have some tendencies to act like an old lady. I personally embrace my grandmotherly qualities. If I could spend all my time sewing/quilting, knitting, and making wreaths, I would be a very happy person, indeed.

Grandmotherliness aside, I am very curious about why I continue to wake up at the same time each morning. I can't help but wonder if I've been waking up sixish hours into sleep for a while and just haven't realized it because sixish hours into sleep was always a different time.

Weird.