Need help fast. Young Cat with broken leg?

Okay, so just a few minutes ago I noticed my cat limping. He got inside and started meowing loudly. He is holding his back right leg in the air and not letting it touch the ground at all. I pressed around his leg, different areas, until I found the pain spot. He cried out loudly when i pressed down on his haunch. So I'm guessing that's where the break is. He doesn't want to move much, and now he's just laying down. For a few minutes he kept meowing loudly, like he was crying. And he was outside when it happened, so I didn't see anything. But luckily he came running inside after it happened, I'm guessing. We tried to give him some pain medicine (me and my mom) but that didn't work out. We currently have no money to take him to a vet, and won't be able to for another month. We don't have a working car either. So please don't suggest taking him to a vet. I can't buy anymore pain relievers for him either. If it is not a broken leg, what else could it be? He's still young, not yet a year old. Any help would be the best. Also, the injury is internal. There isn't any blood on his fur or anywhere else, and his haunch seems a bit swollen.