When I have trouble dealing with what is out of my control, I find that just saying a prayer and giving it to God helps me let go. It also reminds me that I do not have the power over life or death.
When we cannot help, we can pray, to God, to the universe or to whatever we believe our Higher Power is.
I think you handled this remarkably well, and I am glad you will be seeing a therapist this week.
Hugs and prayers for all of you.