You've had a roller coaster of a time, I think its quite natural to want to feel angry, people's reaction to significant life changes can follow the 'change curve' - denial, anger, acceptance, integration. I am sure you went through 'I don't believe it' and now you are in the anger phase. Its completely natural. Thing is the next step is acceptance, when you start your new life for you and your son, with diabetes in the mix. Learning to inject, manage his diet, school all those things will be a complete change. In a few months time you and he will be taking it all in your stride, and you will look back on this week and find it hard to believe that you have come so far!
Keep strong and you will find your way!