Why is my iPod broken after update?

Last night, my apple iPod touch 5th generation requested an update for iOS 8.4. Without thinking any problems would occur I updated it. After my iPod updated, it turned off normally, but after I unlocked it, the screen would turn negative and turn off, then turn back on again. I tried to set it back to factory settings but I had to turn off my pass code, this took about 20 minutes. After I got the pass code off, it would only turn onto the apple icon then turn off. It's been doing this all day. I tried putting the device in reset mode but it won't stay on long enough. I've tried plugging it in, turning it off, then on again. I've tried everything in my power to try to fix it, now the only thing I can think to do is get a new one but I don't have enough money, nor can I go to the Genius bar which is 5 hours away.