A week or so ago I got an iPhone 5 16GB. In this week, the battery runs out stupidly quick (within two hours, even if I don't use it at all or it is shut off completely). At first, if I had Wi-Fi, the battery would act semi-normal, but now it dies quickly even with Wi-Fi. And today I hopped on an app for a minute or two while it was charging and the battery dropped 25%, while it was charging. What do I do? I literally just got this phone a week ago.