Well, I went my upper secondary mainly with 5-6 hours per night and even had my matriculation examination with caffeine. I don't recommend it, I'd have felt a way better if I had slept enough.
But I know the feeling. For some reason, I'm a person who loves nighttime. It's so peaceful and make me feel somehow so secure and serene.
Ah, but my open uni of applied sciences will start 18th in the next month. I just checked the preparative schedule and seems it's a pretty loose course so I'm considering some kind of part time/secondary job. Tho I'm not sure yet.