Personally, I try to never get out of a normal sleep schedule. This includes times when I woke up at 1 PM on a weekend. I'll still try and get in bed by midnight, and be asleep by 1-2 AM at the latest.
One thing that may help is placing your alarm (as long as it's loud) somewhere you can't reach from your bed. I know I've put mine on a table across my room before. This forces you to get up, or otherwise listen to the annoyance for like, minutes until it turns off. Another alarm suggestion is to take a sound that reminds you of something that would jolt you or make you do a double take. For me, this is the marching cadence for the ROTC at my college (considering we have to wake up early every morning there, I hear it and think "oh. time to get up or you'll get yelled at"). Now since not everyone's in ROTC, this could be anything. It could be a siren, a fire truck, a loud horn. Basically, just pick your alarm sounds wisely. I know most phones can do it, and some alarm clocks nowaday let you pick your alarm sound.
Lastly, once you're back in a day/night sleep schedule, try to keep it. If you find yourself staying up until 4-5 AM, set a timer on your computer that will kick you off at 1 AM. Once you get used to it it'll become habit to get off by midnight to 1. Trust me, you probably won't miss much, even if your friends all have the luxury of not needing a sleep schedule. You'll find that there's so many benefits to a normal sleep schedule, like right now it's 9:00 AM, I'm awake, and I hear birds outside. It's so peaceful and quiet in the mornings, and it's something a lot of people miss up on if they're either tired from staying up all night, or asleep.
(more lastly oops) Lastly lastly, that "sleep but not really" state? That's important to help you fall asleep. When you're in that state your body is resting, it's just your mind's too active to fall asleep yet. If that happens, I know it's cliche, but count sheep in your head. Imagine them in a meadow just being herded and count them one by one in a linear fashion, paying attention to the green grass, etc. That helps me get from that "half asleep" to fully asleep state.