Is compassion really a human nature?

Image via Wikipedia

My experience starts telling me that people usually would turn away from you if they heard that you were sick, especially if you are chronically ill. It seems that people either don't really know how to act in such a situation or, they simply don't believe you are sick (unless you stay in hospital).

I cannot tell how many time when I mentioned that I wasn't feeling well to some of my "friends" they just shrugged me off by saying "you look fine", or "you sound fine". I knew clearly what they really said was "don't even try to draw my attention by saying that you are sick", or, "you just don't know yourself". I also noticed that quite a few times people (or friends) just ignored my emails when I mentioned I was not in good shape.
By the way let me just clarify here that I was not the type of person who like to whiny over nothing.

So as time goes by friendships are jeopardized. As matter of fact I had to drop a few friends (which was not easy to me), because I simply cannot imagine I would do the same things like what they did to me. I can't even recall a single time of turning away from a friend when she/he needed me.
Am I abnormal here? Or, am I just too good to be a human being?