Is it normal to miss depression

It has been almost three years since my mom died. She committed suicide by slashing her wrists and then got in her car and drove into a tree. There was no note or anything. My family finds peace in the fact that she was going in the direction of the nearest medical facilitie and they assume she was going to get help and passed out whole driving. They are probably right about this, however my thoughts always come back to the fact that we don't know that. All we know is that she set out to kill herself and she did. At first I was depressed. But over the years I find myself more bitter and angry and less sad. Since her death she has missed the birth of her granddaughter, 8 birthdays for her grandchildren, 2 Christmases, 2 thanksgivings, 3 easters and my wedding. The more events she is not at the less sad I am and the more angry I am. The more I feel as if she chose to miss it. I feel that by choosing to take her own life she chose to not share in our lives with us. I find that the only thing I am sad about is that I am not sad. Only bitter and angry. Is this normal?