Sandisue,
I can only imagine how hard it is for you to work 3rd shift. There are many times where I just can't sleep in the wee morning hours and would always think that I
should work a 3rd shift job as I'm awake anyhow. On the nights that I can't sleep it messes my whole day up as I'm so sleepy during the "daylight" hours.
I am a person who has to sleep with a fan on - although, there are times when even that doesn't help me to sleep. For me, it's trying to turn off my "brain" from thinking about all the things I should or need to be doing. When I know I need to get some sleep that seems to be when I toss and turn, toss and turn all night - very frustrating.

For the most part, I would say the "average" sleep I get in one night is five hours. There are days when I can sneak in an hour nap at some point and it sure feels good!

Are you a "nap" person? They can really help - even if it's only a short one.
I've just started a new job which has me working different hours - daytime hours and evening/weekend hours . . . I've noticed my "sleeping" is all messed up too. On my days off all I want to do is sleep the whole day but I have grocery shopping, cleaning, laundry, etc. to get caught up on. On work nights by the time I get home in the evening my family is getting ready to go to bed. It ends up being a "hi" and "bye" situation and trying to get caught up on what's going on with them at school and work. (I just went from a stay-at-home mom for the past two years, and now having to return to work again.)
There are many days when I feel like my family and I are two ships passing in the night.
I hope you are able to transfer to a different "daytime" job with less stress that will be a perfect match for you.
Best wishes,
Bucky