Next stop is the Apple counter and hope you have the warranty.
I had my phone charged at 100% this morning, and didn't use it all, and when I took it out at lunch it was at 1% and then died. So now I'm home, and whenever I charge it, it takes about a half hour of charging to even turn on, and then it just stays at 1%. I've already tried 3 different chargers and it's making no difference. I've rebooted it many times and turned it on and off.