iMore

Starting yesterday my iPhone 4S had no service. Whatever I tried, it just wouldn't let me send any texts or use the internet without wifi. Before that I had started updating my phone to iOS 8.1 but I had to leave so I just turned my phone off. Fast forward to a few minutes ago, I decided to try updating my phone again and soon after a screen with a USB cable on the bottom with an arrow pointing towards the iTunes sign popped up. What does this mean and what should I do? I'm so confused.