Try recalibrating it. Remove all the apps in your taskbar first.
Step 1: Launch one of the stock apps on your iDevice (Weather, iTunes, Stocks, etc.).
Step 2: Press and hold the power button until you see the "slide to power off" prompt, then release the power button.
Step 3: Press and hold you home button until the the "slide to power off" prompt disappears and the app force quits.
You should now be on your home screen and your home button should be recalibrated!