You can live longer than that. My boss at work is 66 years old and she can still ride a bicycle for 20 miles.
Talk to your doctor. If you smoke, quit. If you drink, cut back. If you eat a lot of fatty foods, change your diet. If you don't exercise, start exercising right away. It's never too late to change. You could live for another 20-30 years, not 3-5.