Welcome to Fluther.
One thing that I would do (have done) is “remember this lesson for next time”. Obviously, you should have asked the questions six months ago or more, so that’s one lesson to keep uppermost. But that’s not helping you “right now”, so … back to that.
Since it’s winter in the Northern Hemisphere you need dry shelter first, so consider how you can get that. (“Warm” dry shelter would be ideal, of course, but you can live without heat.) Be sure to save all of your warm clothing and rain gear, and keep it in good condition. Give yourself a crash course in sewing, and repair frequently. @marinelife‘s idea about moving from place to place with your vehicle is good, to a point, but if that vehicle is at risk of being repossessed, it’s dangerous to store all that you have in it, because once it’s found – and the odds are that it will be found sooner or later – when it’s towed, then there go all of your possessions, and no way for you to recover them without paying what is owed on the vehicle. So keep that in mind if you’re playing that cat-and-mouse game. If you can sell the vehicle to get some ready cash, then consider that will you still have the option. Even trading down for a lower-value vehicle and some cash – now that you know the value of having a few spare dollars in your pocket, they will last longer – might be wise.
If you can exchange any services with anyone for that shelter, then it will give you allies that you can gradually build up or rebuild your personal network. As a SysAdmin, which is a fairly esoteric field for the common folks whose help you need now, what else can you do? Tax preparation? Wood cutting? Maybe apply for work at Best Buy as part of their Geek Squad or similar?
@Dutchess_III‘s advice to seek work with temp agencies is good. (One of the reasons that I mentioned tax preparation is that it is that season now, and they do hire a lot of temps who can grok the various complexities of tax rules and then follow them. You should be qualified to at least run down that road, even if you don’t have current training or experience.) I got one of the best jobs I’ve ever had right after an unexpected layoff. I went out on a temp job, showed the folks who had hired me a whole lot more than they had bargained for, and it led to an offer of permanent employment with full benefits in short order. Part of the trick in temping is to show how broad your talents are, without too much specialty detail. That way you appeal to a broader selection screen, and when they hire you as “a body to fill a slot” and you bring a brain with you, they can find room.
And strange as it may seem, you might find work by volunteering at a soup kitchen or homeless shelter. Obviously, you’re in need of those services yourself, but they are “jobs” just like many others, and they need capable, willing people to perform them. You might even find permanent work with a foundation or charity via that route.
I’m assuming, of course, that you’re normally capable, ambulatory, sighted, etc. If you have particular disabilities that you have not mentioned, then that makes this all a lot tougher.