Ipod won't turn on. Just flashes apple logo

I have 64GB Blue iPod Touch Personalized that I purchased in 2013 (not sure what generation that was, whatever was being sold in the April timeframe). I use it at work and it's not connected to WiFi and I don't bring it home very often to be updated. The last time it worked it looked like it wanted to do an update but since I was at work and couldn't connect to WiFi I didn't do anything. The next time I went to use it it had shut itself off, even though it was pluged in to a docking station and now when I try to turn it on it flashes the apple logo and then it slowly fades away. I brought it home and let the battery die hoping that would help, left it charging on my computer for a day and all it does while connected to the computer is flash the apple logo and then fade away. It does not show that my Ipod is connected in Itunes and it doesn't look like it's charging because every now and then when I unplug it it flashes the low battery screen, on occasion but not every time. I've tried the home and sleep button to no avail. Help!