Sujaya... First of all, I just want to acknowledge that I am responding to your post when I should be doing PILES of readings and research for papers... but I really felt drawn to this post because I can completely sympathize.
Stay away from Cafeteria food. Cafeterias, like most buffets, are filled with cheap, cheap ingredients. So terrible white starches, those terrible vegetable oils, sugars, corn starch, preservatives, soooo much sodium, flour... just don't do that to your body. Your body is already under so much stress as it is, so untop of all of the sleep deprivation and caffeine over-dosing, DO YOURSELF A FAVOUR AND KEEP AWAY FROM THE CAFETERIA. Fill up on the good stuff... and this is totally doable on a tight schedule and a tight budget.
This site has helped me while budgeting: http://www.poormansatkins.com/
Also, if you're having trouble stress and feeling the physiological effects from it... I recommend lowering the fat intact, if you are on high-fat low carb, and upping the lean proteins. I only say this because too much fat alongside of high cortisol levels will only make those stress symptoms worse.
Just focus on feeling up on the good things. Don't binge! If you're like me and need to munch or drink something while under stress and focusing... then drink hot herbal teas or black coffee. It kills any sort of appetite and I find it very calming.
More importantly, focus on your workload right now. Focus on getting those A's and B's! It is hard to fit in food planning, grocery shopping and exercise during these times... But you can still do all that you can to prevent gains.
I tell you all of this because I have been there and am currently there as we speak. It sucks. BUT WE CAN DO THIS!