Hi there! I too am a student so I know how difficult it can be to juggle schoolwork, working out, and eating well!
The above is sound advice. I'm a big advocate of planning. "Failing to plan is planning to fail" is one of my favorite motivational quotes because it's SO TRUE! By planning ahead, you may never find yourself in a situation where there's no healthy food available. It does take some work and some trial and error, but it's all worth it.
Some good things are eggs/egg whites, protein smoothies, sandwiches and wraps, fruit and nut butter, veggies and/or whole-wheat pita with hummus, oatmeal, quinoa, nuts, tuna and whole-wheat crackers, and bean and grain salads. Remember that frozen veggies can be just as good as fresh (nutritionally) so if you're on a budget, you may want to buy more of these. Eating more vegetarian meals is not only good for your waistline, but good for your wallet! Try eating more beans, eggs, and tofu in place of meat. Ideally, you want to stick to whole foods as much as you can.
Hopefully this helps; if you need anything else (recipes, workouts, etc), please let me know!