Dorothy I feel for you....
Feeling angry is one of the first stages of grief. But I believe you must also start feeling sad and finally accept it, if you are going to start living again. That is why I agree with Psimer, regarding therapy.
I am sure you also feel helpless and guilty for not being able to stop him dying! And this can only be addressed by therapy or prayer .(?)
I have done both. Both have helped me in many ways to deal with my baby's death. She also had a heart condition and surgeons tried to dril a whole in her heart to stop her from dying!!( 17 years ago, TODAY!)
So, start doing something, rather than fuming and blaming.
I do understand your pain.
God Bless you!!