Sprint HTC Hero :: Phone Died In Middle Of Taking Video - Restored Factory Settings

My phone died in the middle of taking video. Came home a couple hours later, plugged my phone into the charger. I turned the phone on, after it was plugged in. My phone froze during the little HTC and Hero intro. After the freeze, it was back on, but my screens were all back to factory settings! It also asked me to calibrate my keyboard, and the little popup bubbles to guide the user with their "new phone" came up! All my apps were gone!! I lost ALL of my contacts! The only thing that stayed was my pictures and videos. It doesn't make any sense to me.