iPod Ipod 5th generation issue..

[axeldtf]

Last night i connected my Ipod 5th gen to my imac to charge and to transer some new music. Once i connected my ipod the "do not disconnect" screen came up in the ipod. However the ipod never showed up on my itunes app. Also i didnt show up on my desktop or the devices. The battery was 1/4 full on the ipod. So i disconnected the ipod and the screen stayed on the white do not disconnect screen. I tried resetting it and also tried charging on an ac power cord. The only fix was to actually let the battery run down and then recharge it. So far it seems fine but was wondering what caused this and what can i do the next time this happens. Any help would be appreciated. Thanks!