unsettling silence

What sort of emotions should be registered when you hear a family member has passed away? I suppose the natural reaction would be sorrow. Yet I don't really feel that way, all I can register is ambiguity and the disappointment that I'd never be able to meet my grandmother.. Today my grandmother in Vietnam died, my estranged aunt in America told me over the phone. The first thought was my mother, who hasn't seen her own mother for two decades... I didn't know how I was supposed to break her heart by telling her that. The only sorrow I feel is from knowing that my mother will be in heart wrenching pain.