My Phone won't turn on or charge.

So, for some reason my phone suddenly died. When I went home to try and charge it, it shows the low-battery charging screen then flashes into the apple screen. Usually after the apple screen comes on, the phone turns on, but it goes into a black screen and repeats the process. Before when I was out and my phone wouldn't turn on, I thought something was wrong because if it was dead, you would hold the power button long enough and the low-battery screen would show up but nothing. It was just a black screen the whole time.. Somebody help please??