I feel your pain man. When I was seven I really didn't understand what was going on with my mom. She had lung and brain cancer so her days were limited but I was just under the impression she was sick. She called one day and said "you don't wanna come visit mom?" and I said no because I was too involved with my games and that was the last memory I had of her. It'll haunt you for a while, but then you let the good times take over. Cherish those moments you remember with her, it'll help brighten your day up