iphone 6s black out

My phone was charging all night and was blacked out the next morning when i woke up. It has been blacked out for 4 days. When i tried pushing the home and lock button to reboot it, it did not work. My phone is connected to my itunes and i keep clicking restore, the bar on my phone will go halfway and then the computer will say there was an error. What do i need to do?