Thank you for allowing me to respond to your concerns. What I find so interesting about your letter is that it seems to me you are feeling towards the therapist what you have been feeling toward others. Therapy, particularly in long-term therapy, it is common for some of the feelings that you are wrestling with outside to come into the therapy room. Your sentence: ‘I feel rage and resentment towards her at not being there for me when I’ve been legitimately upset,’ seems to merit exactly what you experienced in each of your vignettes. The coworker, your sister, and the guy you dated are all people you had a legitimate gripe with, and you have resentment toward them when they weren’t there for you when you were legitimately upset. In other words I think it’s time for you to talk to your therapist about the commonality of these feelings. The therapeutic environment can allow you to encounter this issue with your therapist with the hope of working it through.
My experience is that when there is such a powerful pull to leave, it is probably time to see how the issue in therapy reflects issues in your life.
Of course, if you do this and don’t feel it is resolvable or workable with your therapist then you may want to move on. But my strong suggestion is to bring all this forward first.