I went through a string of very difficult circumstance some years ago, one after another after another, and was the stalwart we all expect ourselves to be. Some months later, when no more seemed to landing on my plate, I ended up in my doctors surgery with tears running down my face. Like you I listed what had happened and how I had sorted it all out and how I felt proud of myself for doing so and could not understand why I was feeling such a wuss about the little things in life.
I have never forgotten what she said, very kindly, to me. "So what resources are you drawing on now?" I had used up every bit of resource and needed to build them back up. I agree with jinglbellsfrocks, don't be hard on yourself. Let your friend come this time and build towards doing it by yourself. Be kind to yourself and rebuild those resources. You know just how well you have coped with what is a traumatic experience and all that is happening is you are learning new coping mechanisms for a new circumstances and do keep reminding yourself of how well you have done.
from me for someone who has done so well and will do in the future albeit in a different way to the past.