It is kinda weird... But the healthiest thing to do is to accept the way you feel, even when you feel nothing... I have done a lot of work with children, helping them process grief when a parent has died or something of that nature... Many people don't know how to handle grief or lack thereof.
You sound like you are aware of your lack of sorrow and why you feel that way... And because of that I think you're reacting in a very healthy and mature way, and sharing is always good