I'm in the same boat, though I'm just an undergrad. Three more weeks, then finals. Home stretch!

I'm also on campus for approximately twelve hours each day. I make sure my lunch is appetizing and convenient for me to eat. I tend to 'reward' myself with food (which works for me but may not be best for everyone), and punctuate my study breaks with nibbles of my favorite things to eat.

I should also preface this by stating that I am a higher-carb Paleo, and eat about 150-175g a day with no ill effect.

First off, I have to bribe myself to get out of bed. That typically consists of a high-protein/fat meal with a banana with almond butter for "dessert". Yes, I look forward to my daily banana, and I do use it as motivation to throw off the covers and start yet another dreadfully stressful day.

Currently, I'm able to cram about 1000-1200 calories into a handful of food, which is easiest for me. It's delicious, high-fat, and very filling. Currently, my backpack is stuffed with: a Larabar (cashew cookie is my favorite), an ounce and a half of cashews (what? I like cashews!), four squares of 85% dark chocolate, some low-sugar beef jerky or a sachet of tuna or salmon (the no-drain kind), and if I'm in the mood for it, a couple of small plums or an apple or something.

I devour the Larabar in my Stats class (the sugar helps keep me awake, honestly) and after math, I move into the library to study for a couple hours before my next class. The food is easily consumed in the library (unless I pack fish, then clearly I take that outside) and because I enjoy it so much, I'm both physically and emotionally satisfied by it.

Because I get home so late, dinner is typically a dish of veggies and some protein, and yes, more dark chocolate.

I'm not arguing that this is terribly healthy, but it's much better than bingeing on cookies or ice cream (which I am wont to do when I'm anxious, overwhelmed, and famished) and I don't feel the urge to devour copious amounts of unhealthful things, either, because I'm eating exactly what I want. I also keep lots of my favorite teas around to sip on to keep my mouth busy when I do get the urge to stuff my face when no longer hungry. I'm currently sipping some Candy Cane Lane, which I adore.

Anyway. I rambled here. Sorry!

TL;DR: I eat yummy, high-fat things when under duress and it keeps me from bingeing on things that make me sick.

Good luck, Caleb, with the end of the semester! You're almost there. You can do this! :D

I could be wrong but I've read that intense concentration/studying can cause the brain to burn through a lot of glucose, so it could be that you should up your starchy carbs??

What do you eat on a daily basis? Maybe you're not getting enough fat? Do you allow fruits and starches? Maybe you need them to make it through the semester if you otherwise avoid them for some reason. Good luck making it through, I definitely have been where you are right now, though eating SAD and getting through on sugar rushes. Good luck.

It's a tough series of questions you ask.

My opinion is that there are likely a multiplicity of factors at play. Some might be nutritional and/or related to your current physical state and others might be related to the stress you're under, the peer pressure you could be feeling, family relationships, any insecurities and so on. From personal experience, I believe that an almost infinite factors come into play.

All I can tell you is that you're going to be fine and get through your grad school. I was there once and I could hardly see the light at the end of the tunnel. Make your best choices and don't be too tough on yourself.

It's hard, I know, but I think your best option would be to make sure you are eating regular meals. Keep lots of quick and easy paleo foods in the house (or in your backpack), and set an alarm on your phone or watch to make sure you are eating on a regular basis. When you go to long without food, your body wants whatever it can get its hands on.

But, I wouldn't stress out about it too much. Grad school isn't forever, and it is stressful enough as it is. Just do the best you can until you are done.