Okay, you're in a difficult situation.
Could any of your friends/acquaintances take you to food bank (or bring you food from there, if you wrote a list of what you can and can't eat)? Or would this be too embarassing/difficult to ask or something like that?

Sorry to hear you didn't get the job. Did you check for any other postings for people with your skills? Idealist.org has many postings for NGOs, I'm sure many would appreciate your skills! Some can be done remotely too!

How much do you need to stay alive and have food till the next food stamps/money transfer?

PS Read the PM and answer