my iphone is messed up

my iPhone storage is full so i deleted 15 GB of pictures. all of these 15 GB has gone into the apple system called "other". everything i deleted goes into that "other" and now i have 30 GB out of 64 of "other". my apps aren't opening because i have full storage and i'm exhausted. i cant back up my phone because every time i connect it to the computer is says "device unconnected". help!!!