Sounds like you reset the phone from the settings menu, correct? Try this:
Hold Volume UP, and the home key down at the same time. Now, while still holding those two keys, press and hold the power key.
When you see the Samsung logo you can let go of the power and continue to hold the other two keys. You will see a screen with blue text that says "Android Recovery" at the top.
Now use the volume down key to scroll down to "Wipe Data" and then use the power key to select it. On the next screen scroll down to Yes then again select it with the power key. This will hard reset your phone.
When it boots up, allow upto 15 minutes for it to fully boot.
Report back with what happens!