iPod 5 won't turn on

I was out skating all day, and my iPod was working perfectly fine. I stopped by my buddy's house, to charge my iPod. So it was at a good 50 percent when I unplugged it, and left to catch a ride home. I put it in my pocket, and it was only a 5 - 10 minute drive. I took it out, and tried to unlock it but it wouldn't. It was just black, for no reason at all. I tried charging it for an hour and a half, nothing. I can't reboot it because the power button is broken on it, and I can't connect it to a computer right now. What do I do? Why did it do this?