That sounds neither sad nor crazy or anything else people might tell you. It's quite normal. You maybe an introvert. Which is not what most people think it is.
This maybe the best article on the subject and most popular Atlantic Monthly article ever in terms of reader response: http://www.theatlantic.com/magazine/archive/2003/03/caring-f...
If that rings true, Welcome! You are far from alone. But we'll leave you alone, because we're the same way most of the time.