My answer to this is wholy unqualified, and I'm just giving my first thoughts.
good sleep practices will be your best tool here.
a) make sure you're in a totally dark room, or wear one of those eye cover things. Or a long sock tied around your head to block all the light.
b) start running cool water on you feet for 15–30sec first thing in the morning. And then eat breakfast. This will help your body know when “wake-up” time is.
c)Avoid any and all screens for at least 30 min before bed, phone, computer, tv, etc. Even if the have a “"night shift” option.
d) read a book (a paper one) by candle light (if your parents are okay with you burning a candle) if you really can't sleep. If you can't use a candle listen to a quiet audio book till you fall asleep.
E) try to go to bed, and wake up at the same times every day, even on weekends.
F) once you have those things in place you'll be doing most of what you can to get your body's natural sleep rythem running properly, so pick a time when you don't have any tests in school, and ditch the pacifier. If you don't sleep the first night, it will definitely not be fun and you'll be a zombie the next day, but my the second night you'll almost certainly fall asleep.
G) if you're really, truely, not able to sleep without the pacifier try talking to your parents about getting some help. Additionally you can probably talk to your school counciler.