Day 35Ah, screw it, who gives a stuff about dates? If this all blows over you'll figure it out afterward.

You've been trying to dig out the hole under the grate. Results have been... unconclusive. Getting the ground outside with nothing but a small cardboard box is extremely slow, tedious, and taxing on the air system, so for now you've abandoned that idea.
At the very least, the supplies you currently have on hand - the usual consumables, like food, water and fuel - are going to last you a week and a half. Water'll go first. You've been thinking of filtering rainwater, though you're not very sure of the specifics just yet. You might be able to use one of those water filters people use to drink from rivers - but frankly, you didn't think to get one before the world went to stuff. Still, you reckon it can't be that hard to find one. While your bunker's in a barren field, the town nearby had quite the few residents. You should be able to find one, given how road trip loving everyone here is. Was?
Either way, you're going for another trip tomorrow. These trips burn through gasmask filters like it's nobody's business, and you only have filters left for six or so hours of unfiltered air. You're going to grab more from where you can.
Filters... This bunker's meant to block everything, but at least you can still get a decent radio signal out of it. Most radio stations have shut down, but some smaller groups still run amateur stations, reporting the situation. The country's pretty much dead. Utilities have nobody left to run them, and power has completely shut down in all but a few corners of the south-west, where some people have banded together to run a good chunk of the grid using nothing but solar.
To be perfectly frank, few people were ready for this kind of end. Sure, you've got tons of doomsday enthusiasts that were already prepared for a zombie apocalypse with more guns than they have ammo for. Unfortunately, few of them expected the disease to be airborne.
There are still some parts of the north where people can make trips out without a gasmask - it's just the wilderness; the less population, the slower the spread of the infection. Hell, you wouldn't be surprised to hear of people in Washington surviving just well in a month's time, or in Alaska in half a year.