My iPhone restarted itself when i synced it to my iTunes, now everything is gone, how can i get it back?

I plugged in my iPhone 3GS into my computer and it asked if i wanted to sync it to iTunes. I thought it would be a good idea, so i did. My phone then turned off and then back on again and now there is a whole new background, everything is disorganized, all my videos, photos, and contacts are gone! The apple support wants to charge me 30 bucks for a service fee, so please dont suggest i call them. Does anyone know how to get all of this back? Please help!