iPhone 6 problem

[iamdeejaay]

So last night I plugged my phone in before I went to sleep to charge. I woke up this morning and after 5-8 hours of charging, I pressed the home button (while it was still on the charger) and it read 89%. I thought that was weird because it was on the charger for over 5 hours. So I unplugged the charger and the screen just went black, now the phone won't even turn on. I've tried holding the lock & home button at the same time. I'm just wondering if anyway here knew what this could be. I was thinking maybe a battery shortage. But if anyone knows anything that'd be great! Thank you!