Go to bed early. Be careful to not do anything in the bedroom except sleep or sex, or read a book.

And get up at a “normal” time. Make sure you eat meals at customary times, and eat dinner by seven, and nothing afterwards.

Meanwhile, no coffee or tea after breakfast. And no sweets and very moderate alcohol. Both can disrupt sleeping patterns.

Do all that and you will be on schedule in three or four days

Welcome to my life. The other day I was up for around 50 hours straight.

Right now my schedule is bonkers.

I went from a east facing window with no covering on a the window to a south facing one with blinds. When I had the east facing one I was blinded by the sunrise and was getting up at 5am everyday and I was totally fine with it. Today with the south-facing one I woke up at 11AM and my room was completely dark.

So light. Get a big ass lamp and a timer. I am about to do the same.

Why does it matter? You get to sleep while the bulk of your peers deal with the tedium involved with 9–5 drudgery. I assume you’re awake when their workday is ended and they’re free (if they have the strength) to interact with you.

@zenvelo is correct. At the moment, my pattern is much like @johnpowell.‘s This is what I have to do: as of this moment, I have been up since just before 3am Monday morning. It is now 3:31am Tuesday morning. If I am to get back on track, I must hump it through to at least 8pm tonight, then sleep until around 8am Wednesday. Then I will be a bit tired, but OK and back on schedule.

If it’s important you straighten it out. Go to bed later and later until you circle the clock to a better time. Do it over a long weekend. Being exhausted will help you fall asleep “early.”

Exercise at least three times a day.

When you get the sleepy feeling at night don’t let it pass by! Get into bed, get into your sleep position (mine is my left side) make sure your not hungry and your feet and hands are warm, and close your eyes. Studies show cold feet and hands makes it hard to fall asleep, and it’s definitely true for me.

No caffeine after 3:00. Or, whatever you figure out that helps. Less caffeine overall. Or, quit it. Although, know that it’s not like quitting caffeine puts you automatically on a nighttime sleep cycle. It’s just that being on caffeine can affect how sleepy you feel.

If it’s not important to sleep at night then don’t be so worried about it. It will probably straighten out over time if you want it to.

Years ago I used to “commute” to Japan about once per month. That was a 13 or 14 hour time difference. I needed to switch my internal clock quickly so I’d be running on all cylinders while at the office.
My goal was to get my clock to match the destination time. I would do that by either forcing myself to stay awake. Or take 2 benadryl and sleep lots of hours on the plane.
It worked. If I arrived on a Saturday I’d be “up and at ‘em” on Monday morning.

I also changed my bathroom habits from a morning poop every day (every 24 hours) to an alternating schedule (every 36 hours) – sometimes at night sometimes in the morning. This is actually easier than it sounds – and not as weird as it sounds.

(I’m back to every morning now, if you’re interested.)

I’m trying to do the same thing right now. I tend to get a 2nd wind around 9 p.m. when I would like to be in bed by 9–9;30 most nights to feel my optimum. The trick is to force yourself to stick to a regular sleep schedule. When you are finally, sufficiently tired, make yourself go to bed at a decent hour then stick to that schedule. I tend to do the same thing when stressed, get into occupying my mind instead of just going to bed.

I use the same technique my dad always forced on us when we had to deal with a time change – stay awake until the next time the locals (or people I’m supposed to be interacting with) would go to bed. Sometimes it means forcing myself to stay awake for an extra 12 – 16 hours to get to the ‘right’ bedtime.

I get the same thing as @Coloma by around 9 pm I am so tired. The more tired I get though the more I fight it. I have a mood disorder so probably it’s this ‘nuttiness’ that causes me to fight it. I’ve had an idea, as also I think it is an anxiety about going to bed. I have bought an inflatable mattress which is in the lounge, perhaps I will doze off in front of the TV and then if I wake up, go to bed. Once I am asleep I love it! it’s 4 am and here I am.