This is apparently a Moen Monticello, and your handle is BROKEN.
The large ball below the lever unscrews, to remove the handle from the valve. There is an infamous plastic adapter connecting the ball to the lever part, and that is what is broken. Moen might send it to you under warranty. 1-800-buy-moen
This diagram may help>> http://www.moen.com/shared/pdf/T952pt.pdf