I've been working the nightshift off and on for the past 30 years. Truthfully, your body never really gets used to it. We're not nocturnal creatures, we're designed to sleep at night. As nightshift workers, we have to "con" our bodies into thinking that we're sleeping at night, or we're going to suffer.
There are several ways to do nightshift. It depends on your home environment.
Make your bedroom as dark as you possibly can. Tint the windows, or cover them with something to completely blacken out any light in your room.
Turn off your telephone. People are under the impression constantly that just because they work in the day and sleep at night, you do too. Not true. People will call you all the time and say, "Did I wake you up?" And you will have a hard time getting that needed sleep your body needs.
Run all of your errands BEFORE going to bed. Get all of your business done, so that you can get as much uninterupted sleep as you can.
Don't rely on sleeping pills, even the over-the-counter ones. It's artificial sleep, and you will pay for it dearly.
Just as your sleep patterns are going to be different, so will your eating habits. I found a crock pot to be my best friend. Take a roast, some carrots, potatoes, onions, etc.... toss it in there before going to bed. Sleep all day, and when you wake up, one nutritous meal waiting on you. You can't overcook it, or burn it. Just load it up, turn it on low, and go to bed. Take a meal to work with you. Then you will at least get two good meals per day. Once you are up, you have time to exercise. I have a Bowflex gym and a stationary bike. I try to knock out 20-30 mins every other day. Nightshift can make you soft if you let it, because you are reducing your physical activities.
I usually lay off the caffiene after 4:00am. It's ok to pour down the coffee before then. But after 4:00am, I stop because I want most of the effects of the caffiene to wear off before morning so I can go to bed and sleep.
On your "Friday", try to sleep maybe 2 hours when you get home. You don't want to waste your whole day off in bed. I know it's tough to function, but you'll get used to it. And then that night, go to bed and sleep all night like a human being.
On the day that you have to go back to shift work, stay up all day, but in the evening, around 5:00pm, or 6:00pm, go to bed and get 5-6 hours sleep before your shift. Then you will have enough rest to get you through work, without feeling the effects too badly.
It takes time getting into a routine. And you might have to adjust a little here and there to get your body with the program. Yes, nightshift is less stressful, depending on the job you do, but like I said, we're not hard wired to be nocturnal. So we have to "fool" our bodies into thinking we're getting enough sleep.
One more thing........once you get a pattern going, don't deviate from it, if you can help it. Or you will be hurting all night!