Could my despair be an emotional flashback? Could my psyche be trying to hold me back? Or am I just delusional?
I think it is a combination of the first two. You/we will go through a struggle with our self as we try to change thoughts and beliefs and behaviors. Those are lies that you were told and they sunk in deep. Your mind will want you to go back to its 'normal' state even though that state was not healthy. Your mind will try to pull you back to what is comfortable, in much the same way our family members try to do.
Keep using the tools you now have:
-Your therapist
-Us here
-The articles on the inner critic (understanding it and battling it)
-Asking yourself how you would feel if your kids experienced what you went through if you would feel it was no big deal?
Those are 4 very powerful tools that you have learned and will continue to learn to use as you work your way through this. You will pick up more along the way.
Healing and recovery is an active process and we have to push (within reason of course).
Periods of grief will happen as you heal and, as difficult as they are, are good signs as it means things are changing.