The Sony Xperia C is an Android phone which was released in July 2013. It features a 5.0-inch display with a ~220ppi density and an 8MP rear camera. The Xperia C can be identified by the model number C2305.
Have you tried turning it off and turning it back on ?
If you have , back your phone up to a pc then reset it. Hopefully that helps since there are some rare strange bugs in android fixed by factory reseting your phone.