Is my iCloud/ iPhone hacked?

I suspect that my icloud account has been hacked on my iphone. I have reset my iphone to factory settings and deleted my old iCloud account and created a new one, but the phone still behaves oddly. Internet/WiFi isn't working as it should, apps that I never use like "the stock", "itunes store", and several other pops up when I double-click the home button to see wich programs iv'e used. Common programs that pictures and videos behave differently, it feels like the iphone is hacked somehow. What can I do to fix this?