I'm a university student (USA) that currently shares an apartment with 5 other people, 2 people to each room. Typically, I have to get up early to go to work and then go to school after that. This means that I go to sleep much earlier than most people my age (around 10:30 P.M. most nights), so I can function at work in the morning. My roommates operate quite differently (going to bed after 1 A.M. most nights). Our walls are extremely thin, so if they are having a lively conversation, or if they are watching something, it bleeds right into my room. Additionally, my room roommate will burst into the room in the middle of the night, turning on the lights, waking me up from my half-sleep, as he tries to get to sleep himself.
This morning was a breaking point for me. Apparently, three of my roommates stayed up the entire night, burst into my room at 5:30 in the morning (shortly before I would normally wake up), waking up my other roommate, so that they could tell him of their night's escapades and go eat breakfast.
How can I let my roommates know that their noise is affecting my sleep in a tactful way that won't make them see me as a stick-in-the-mud (I consider these people my friends)?
TL;DR: How can I tell my roommates they are being too loud without them hating me?