hi, i have a second generation ipod touch, and i recently upgraded it to the new IOS. Today in the morning i saw it had almost no battery, but i was in a hurry do didn´t plug it to the pc. when i got home i went to turn it on and it had no battery, i plugged it and since then all it does is stay in the low battery screen and then to the apple screen, turns off and repeats...help?