I had this problem BAD when I first got on the road. I had packed barely anything in a swiss laptop back pack. i forgot clothes, sleeping bag, and an actual pack would have been nice. I packed in about 5 minutes, growing more insane every second. It wasn't too bad during the summer, and that first night our mutual friend let me use his sleeping bag. I didn't sleep that night, ended up giving it back after an hour. The next day a guy at Sox Place in downtown Denver gave me his old sleeping bag, and I sewed shopping cart straps to my back pack to keep it in place, and then my other friend gave me one of her sweaters.
Some people on the road are very generous and willing to help you out. The latter mentioned ended up leaving me in downtown Denver cause they didn't want to travel with a runaway, and I don't blame them. They helped enough. And as the days went on and turned into months clothes just came and went. stealing, groundscoring, handouts, DIY. My parents always told me this world and the people in it would chew me up and spit me out. This is partly true, but I think the world took better care of me then they did.
sorry for the long post!
-labea