School and work seem to be designed to make it impossible to stay healthy. I'm sorry to hear that your in that position but congratulations of going to school and being willing to put yourself through the challenge.
The thing that has helped me most when it comes to eating is to find pre-made heathy options that I can carry with me throughout the day. In stead of trying to hit three meals a day I have everything that I should be eating (in finger food form) in bags and then snack throughout the day. By having everything already planned out I don't have to worry about overeating during the day. This is great for when your in the car for extended periods of time as well: it is easy to great a handful of nuts or baby carrots instead of whatever junk you end up having to settle on usually.
I usually make all of my baggies on Sunday and stick them in the fridge in shopping bags so that there is no prep time in the mornings during the week.
The one thing that makes all of the difference when it comes to how healthy I feel is how much water I am drinking. A water bottle can make all of the difference. Being dehydrated is the fastest way to feel run down.
Other things to try: Vitamins, walking outside (the sun and exercise are a great combination!), stretching whenever there is some down time in between deliveries or classes, and getting more sleep.
I'll definitely try this out. I appreciate it. I found that I can manage to continue through beef jerky, I just need to drink a hell of alot of water to compensate for all of that sodium.
I hope that some of these suggestions are helpful. Congratulations once again for deciding to pursue higher education, hopefully you can make it through as quickly and painlessly as possible!