When you say screen saver do you mean your desktop (common mistake)?
You probably are in extended view and your MacBook is showing normally and all you show on the tv is an extended desktop. Try dragging a window (like your Safari window) off the MacBook screen to the right.... did it start to appear onto your tv? If not, try to the left instead.
If you goto System Preferences/Displays you can make adjustments to the way an external display (your tv) is handled. One option is to select Mirror Displays and both will show the same thing.