Yes, it's entirely possible to live without food for several weeks, more if you are obese.
As long as you have running water, whether it's drinkable or not, you don't need toilet paper.
Potable liquid to drink is far more important. I recommend looking around for homebrewing 'starter kits' that give you the essentials- a fermenter, some bottles, and a bunch of other stuff if you want to get all scientific about it.
You don't need to think about this too hard. Just use the sterilizing powder in decently high concentrations to clean out your fermenter, then get canned malt with yeast to get you going. Heat the malt cans in boiling water to get it flowing easily, don't let it bulge and explode or anything, but heat them up and pour them in. Clean them out with boiling water poured on and filled with a bit of cold to get the most out of them, then fill up the rest of the fermenter up to 20L with cold water.
Make sure your airlock has enough water (with a little sterilizer added) to stop stuff getting in from outside, but not too much water that it washes back, and leave things until you don't hear a bubble more than once every minute or two. You can use a hydrometer if you want to be all flash.
Make sure you have sugar- ideally, special sugar drops, for maximum laziness- ready to add for that time. You can use small bottles or 2.25L Coke bottles if you want more of a session-sized drinking container. They need to be sterilized before adding the beer and the sugar for the secondary fermentation. It's all in the pouring.
As long as Anglosphere governments aren't serious about dealing with this problem, we may have to do a lot of drinking at home. It's important to be ready.