Oh hun it's damaging me to, thank you hope you feel better too
Well I have this same problem, not the jaw thing (I don't think, so sorry can't help with that), But I stay up almost all night, and sleep most of the day. This is more of a message of relation rather than giving advice, sorry at my age you can't really give that much advice. :) Anyway, I know it physically and mentally has been damaging me, buts that's probably because I am so worried about school work (which I know is probably nothing compared to the outside world)... But it's not easy as it is now. Anyway, I hope all goes well soon. :)
Depends on the person -- we all have different body clocks. Most animal life is geared to operate in the light and quiet in the dark, but humans have artificially altered this pattern for centuries, so again, it depends on your personal body clock.
Making change to your sleeping cycle could cause some physical effects. If you plan on doing this for a long time, your body will adjust. A bit more information would be helpful.
Take Care :)
I would think that if you are a night shift worker, sooner or later your body would adjust to the sleeping schedule that you have. Not much is known from your post especially as to the why you are sleeping upside down...
Please post back and write a little more info...
Good luck to you
M