barmeyoldbat - my thoughts are with you. Any death of a close family member is hard, but the death of a child has a sense in unrealism. Nobody expects to outlive their children.
I do hope that you have friends and family around you. When my youngest died, suddenly at the age of 25 years, I just wanted to talk endlessly about to him to anyone an d everyone.
You will need a good two years mourning to recover - a day and stage at the time. It is - for me- twenty years ago - but still miss him. Yes, I mourned my parents when they died in their 80's and my brother in his 70's, but they were 'sad' times, not the tragedy of a young adult.