Welcome to this wonderful forum. I'm sorry that trauma brought you here. But this is a good place to be. I can relate to your physical reactions. What I will say is that the "grief process" is amplified so much more with PTSD, but you still go through it, along with learning to recognize how you and your body deal best with the losses.
You did not deserve that day. I wish I could delete it from your experience, and how it is affecting you and your adult kids' lives now. What I believe is that you are a good person who will now reach out and find lots of support and growth and find blessings on your path.
You'll have good and bad days, just keep going on the bad. It gets better, it really does.