I'm in the same situation as most of you... Maybe better, maybe worse. I don't live at or near my host ROTC school, or even my own school. In fact, I live in a completely different borough. I'd estimate that commuting takes at least 25% of my day. I have to wake up at 0330 to make it to 0650 PT formation. Not fun. On ruck march days, it may take even longer to make sure I have all my equipment squared away. Then, my school day ends at 1945 (7:45 PM)... At which time I'll probably be home by 2100 if I'm lucky. Not to say I have it worse than anyone else, but just to give you an idea that it's possible you can (and will) survive.
If you commute at all, sleep on the train/bus. As much as possible. Probably a no-brainer, but I find it hard to do myself on the LIRR over here in NYC. Also, I'm guessing and hoping that you have a few gaps in your schedule between classes. Take advantage... Go back to your dorm or a quiet library floor and get some shut-eye for the lack of sleep. My school has a 4th floor in the library with a bunch of couches exclusively for sleeping. Awesome. On days when I really can't hold myself up, I have to rely on caffeine... I use 5-hour energy, which is expensive, but also the only one that works for me.
Aglahad is also correct. You should carb up, hydrate, and rest the night before. Stretching should take place just a little before PT begins. The rest is miscellaneous help for the fatigue: never stretch cold muscles, eat bananas and drink coconut milk for cramps, and hydrate, hydrate, and hydrate again. Don't restrict yourself to following the 3-meals-a-day rule; instead, you should eat portion-controlled, balanced meals whenever you need the energy, or whenever your body tells you that you're hungry. Snacking is better than overeating in one session, and skipping the rest of your meals. I haven't fixed this habit yet myself. Personally, I feel like PT wakes me up for the morning, but by my afternoon and evening classes, I am a walking zombie. All of this goes double for an especially difficult college major: any of the hard sciences, engineering, an intensive liberal arts program, pre-med, pre-dental, econ, finance, etc. You're really going to have to work with your schedule if that is the case.
That's really about it.. People have gone on fine with fewer hours of sleep than you and I have. Over time, your sleep rhythm will adjust. I personally believe that as your fitness gets better through PT, so will your overall daily performance with fewer hours of sleep. And finally, on the day of your MS class, just a personal tip: don't fall asleep in front of your MS instructor. I learned my lesson. He/She is not there to sympathize with the lack of sleep. You can afford to doze off for a few seconds in your regular classes, but don't let it happen with the military... Our MSII instructor is an Airborne, Ranger-tabbed, Field Artillery Captain. You can just imagine what he'd expect out of his cadets. I got extremely lucky he just let me off by standing up for the rest of the lecture. Don't do it!
Best of luck. Hooah.
), but he actually had more privacy and a lot more food. Now as a 4th year, he's a short timer and school is easier. 