I can’t make a diagnosis on the basis of a letter, of course. But I can tell you that everything you report is consistent with a diagnosis of depression. I don’t know why you think you aren’t depressed. Feeling hopeless, devoid of emotions, and uncaring about life are all characteristics of depression.
I’m sorry you did not connect with the therapist. But all therapists are not alike. You may not have told her your symptoms as well as you did here. She may not have experience with depression that doesn’t seem rooted in a particular event or series of events. Whatever the reason, the two of you didn’t connect. That doesn’t mean that therapy isn’t for you. It does mean that you need to see a different therapist.
I encourage you to make an appointment with another counselor, preferably someone who works with a psychiatrist. If you don’t feel heard, make an appointment with another. It is not at all uncommon for someone like yourself to try out 2, 3, or even 4 counselors before finding one who is comfortable to work with. Take your letter to us with you to show the counselor during the first appointment. It will help the two of your get started.
The reason I suggest seeing someone who collaborates with a psychiatrist is that I think you will probably be encouraged to include some medication in your treatment — at least at first. A counselor cannot prescribe medication. A psychiatrist can. The preferred treatment for depression is often a combination of medication and talk therapy. You probably do need both to get out of this gray mood.
I wish you well.