Welcome to the board. I understand what you say about the fear and the "what ifs" that seem so much worse at night when you lay your head down. My husband's cancer was 2 1/2 years ago and I still have that fear, but it does not come as often, so hang on. Time does take some of the edge off, although I think we will always know that fear. My husband got on antidepressents for about six month following his treatments. They made a big difference, just helped him get over the hump and back to being his "new" self. We do look at life differently since cancer, but I think it is in a good way as we have learned to appreciate each day that we have and to cherish the moments we have watching our three children grow up. I also understand how you feel about your son, we have a 15 year old son also, and a ten and eleven. I think our 15 year old is the one that understood the most and worries the most. Like us, he has learned that fear also. Wish I could take it away for him, but there it is, so we talk to him when he needs to talk and listen to him when he needs someone to listen. I don't think my two younger children fully understood, which I am kinda grateful for.
I know how hard it is being the caregiver, especially during those rough times, as we tend to hurt the ones we love the most. There were times when my husband told me to go away and leave him alone, but I didn't and looking back now he is so very thankful to me for all I did for him. So, hang in there, things do get better.
Julie