Did you change your wii sensor bar placement?
From the menu, click the little Wii circle (lower left), then Wii Settings. Click the arrow or press the +. There's a Sensor Bar option. If you click on that, there's a Sensor Bar Position option. From there, if the option selected says Above TV, you need to change it to Below TV and click the Confirm button.
If that's not the problem, I don't know what is.