Are you over fifty with absolutely no health problems?

I may be falling apart. I have never had any health problems, never get colds or flu. Now I feel a little tired most days, my ears have a hissing sound round the clock and my right knee has something out of place; it makes a popping sound that hurts so I feel unstable on grass. This started this month! It was not like this in December! Someone said I should expect problems by now; I disagree as I am a total vitamin freak. Am I normal?