Is it making a humming noise?
You may have a chain drive opener. Check the gears inside the case. They may be worn and need replacing. Call a professional.
Is it noisier than usual?
You may have a screw drive opener, which may need to be lubricated, and have a few minor adjustments made. Call a professional for a tune-up.
Does your door go 1/2 way down or almost closed and goes back up?
Your motor may need a minor adjustment. Call a professional for a Tune-up. The service technician will thoroughly check all moving parts to make sure your garage door and garage door opener is in top working order.