I've been to the MOM you describe...it is kinda like trader joes, but it's expensive. I'm not sure what the closest TJs is to you, there is one in rockville and maybe one in columbia.
If you are living in a dorm and have a tiny fridge, like others have mentioned, gonna have to keep it easy
protein: hard boiled eggs, canned fish, eat meat whenever possible
carbs: fruit, try and find some veggies at every meal
fat: nuts, olive oil, avocado
Yeah it may be boring, but as far as your living conditions go it's the easiest thing.
Do you work out at the UMD gym?