How can I sleep when I need to be up early the next day?

Some of you know that I have some of the most absurd sleeping habits you can probably imagine.
I have also suffered off and on with insomnia since childhood.

When I need to be up for any obligation (at any time of day, really), I panic and I can’t sleep. No matter how much I try to relax myself or not focus on needing to be up, I get so worked up knowing that I need to be somewhere or do something, and then I’m up. For some reason it is far less stressful for me to just stay up all night and all day, rather than just go to sleep and wake up like a normal person.

How do I fix that? I have to be “up” in an hour.