My Suggestions On Being Homeless
If you are facing cold weather, the first thing to worry about is socks. Have two pair. People will often worry about you not having a coat, but nobody worries about socks, and they are essential.

If you have any money at all, don't buy food. Buy a breathable, waterproof bivvy bag and for comparison between bags. Be sure of one thing - that it is of a breathable material. Otherwise, the moisture will build up inside and you will feel constantly wet. Be wary of cheap bivvy bags. If they don't have waterproof and breathable up front, you will just end up wet from the inside and, if it rains, the outside. It rolls up very small. You can carry it around under clothing. It is crucial in a pinch, to put on over weather-appropriate clothing. This is not a sleeping bag, but a thin piece of material and you may be miserably cold. So, get the XL so you have some room in there for other things, and can maneuver - to sit and even stand up. You can always find something to stuff in there for added warmth, but the waterproof thing with a durable breathable material, is very hard to come by. They aren't as cheap as a storage or garbage bag, but they are worth whatever you have to pay, and this will give you protection you never thought you needed.
A bit of cheap philosophy: remember that what goes up - will come down, but, most importantly, the opposite is also true - what goes down will come up. There are no flat lines - there are cycles in everything. Just hang in there and you will make it through. Some individuals dive deeper than others, but the forces are all pushing you toward the top. Don't fight them. Relax and know that eventually you will come out of this. It sometimes takes a lot of tries to break through the surface, but if you don't give up, you will succeed.
Finally, two pieces of advice:
Make peace with anyone in your past. It's amazing what a simple 'I'm sorry" can do (Burgreen's "I was wrong" may be better). It may not solve your problem, but it will lift weights from you that you didn't even know were there. And secondly, do not antagonize anyone. They have enough problems. And you don't need any more.
And, remember to do one thing. Do whatever you can to stay clean. Clean gets you into more places and will provide you with more help than you could ever imagine.
THAT'S It. Good Luck.