The bad feelings that you have from this incident have purposes, one of which is to help guide you to do better in handling future situations. One way to do that would be to actually sit with those feelings, and ask yourself what you can learn from them, how you can do better next time.

For example, you might decide that when you don't have your right mind on, you will take steps at once to get your right mind back. Or, if you feel unable to do so, perhaps you would take a personal day or sick day. Or perhaps you will avoid difficult conversations on work nights. Or perhaps you will work on being especially slow and attentive, or plan to consult with colleagues, on days that you don't have your right mind on.

I don't know what might work well for you, but I am thinking that it will be easier to forgive yourself, to let go of the self-criticism, when you have resolved to do better next time and have taken the time to figure out how.

With regard to staying in the relationship, I wonder what you might say to a patient of yours who tells you self-critically that she stayed too long in a relationship that was/is pretty toxic.