First of all I am sorry to hear about your misfortune. Second I am glad you are learning from it and preparing to take steps towards being more prepared. Don't feel too bad about living paycheck to paycheck. That will rapidly improve (assuming you make good choices) when you get done with school. I am going to guess that at least 1/3rd of our readers would be in a fairly similar position though maybe with a bit more food in the house. Another third would need to shift some things around or whatever and would be OK. The last third keep enough of a buffer in checking that it would not be a big issue (depending on when in the month).
Your major concern here is food as you have recently run out of it. Once this little bump in the road is past here is what I suggest. Go to your local big box (Costco, Sam's Club, Winco, etc) and purchase the following items: 20lbs bag of just add water bisquick, a big jug of syrup, 20lbs of rice (sticky is what we prefer) with whatever you like to put on it, a big assed thing of oatmeal plus some brown sugar and a huge jar of peanut butter. Not exactly sure what these will cost you but not very much. Also not going to look up calories and figure out how many days worth of food this is but I think you could eat for awhile on this stuff. This is your starting point to get a decent amount of food for a price you can afford. You now have a reasonable start to staples and more food then a disturbing amount of people. If need be buy the first half of the list one payday and the remainder the following payday.
Here is your next step in food. Get things you actually eat. Every time you pick up something get a second one. The emphasis is on reasonably long term shelf stable stuff but having a couple spare frozen pizzas, packages of burger, etc is not a bad thing. If you would get 2 cans of tuna get 3 or 4. Instead of one box of cereal get two. The key is not to eat up this stuff but to continue buying in excess of your consumption to build up a surplus. It is easy enough (at least in theory) to just put the new stuff at the back of the pile and thus rotate your food.
[if you start getting worried about needing this food for an emergency then just get an alternative cooking source or two]
Between these two plans it is easy enough to rapidly accumulate a good amount of food which you normally eat. Getting to a few weeks or a month of food should be easy and with the plan I outlined you will hardly notice it in the overall budget.
Lots of people say they are too poor to save. I would say just the opposite. People who make/ have very little money need to save (for these purposes) much more so then those who make more. Someone who makes 70k a year can take life's minor problem ($400 seems to be the unlucky number for me) in stride. However a set of tires he would buy without a second though but someone who makes 17k a year that is a real issue UNLESS THEY HAVE PLANNED AND SAVED.
My other suggestion is to save cash. I am not talking about money in the bank though that is a very good thing. Banks are closed, they fail, you loose your card, etc. Every paycheck take $20 and put it away. Keep it in an envelope or whatever in a safe place and DON'T SPEND IT. Continue doing this until you've got a months cash expenses (the landlord, insurance, etc can get checks). At a rate you can probably save at this should take a few months. Once you get to a months worth of cash expenses in said envelope look at putting your continued contributions into a bank account.
Anyway here are a couple of old posts which might be interesting; Letter to Maggy, The Emergency Fund. You can read those but they will rhyme significantly with what I said above. My thoughts are somewhat different because his situation is unique as he is still in school.