It sounds to me like you have started jailbreaking and haven't finished cause the same thing happened to me and when i went to setting - general - about on my ipod it told me i only had 300mb of memory instead of 14.8gb and what i did was restored my computer to an earlier time before i did all the jailbreaking stuff and then re-installed itunes and pressed the sleep/wake button and the home button to reset it which made itunes recognise my touch and then i had to restore it using itunes. 🙂