The Brake light illuminates and the first thing that comes to mind is "PANIC", I might not be able to stop! Your first instinct is to immediately press the brake pedal to see if it will stop the car. It would be in your best interest to wait a moment, look in the rear view mirror to make sure no one is right an your ass. If you need to, let off the gas pedal and allow the car to slow on its own for a bit. While the car is slowing, go ahead and turn on your emergency flashers... Yes this is a good time to use them. This will give the car behind you the ability to pull around you if need be and let the other drivers around you know something is up with your car. Now, go ahead and try to slow the car to a stop by pressing the brake pedal slowly. If you find it stops normal, go ahead and get the car pulled in to a safe parking spot. Pop the hood and check the brake fluid level . If there is some brake fluid in the resivoir but slightly low, then you probably are fine to continue to drive the car until you get a chance to get it into the shop to have your brake pad linnings inspected. If the brake fluid level is completely empty, do not try to drive it any further. Have the car towed to the shop for repairs.