Improper picture i'm not sure what i did but i hit something and now when i view let's say a football game the bottom of the screen is cut off. it's a little irritating i've tried everything!!! help???!!!

I've had this TV or almost 3 years -- it's been great. All of a sudden it seems to have a ratio issue. I can't see the bottom of the screen no matter what settings I use. It's cutting off about 20% of the screen. Maybe more. I've had this TV or almost 3 years -- it's been great. All of a sudden it seems to have a ratio issue. I can't see the bottom of the screen no matter what settings I use. It's cutting off about 20% of the screen. Maybe more.