I say I feel disconnected, like I'm an alien from another planet.
I also say I feel different from other people and isolated.

God is it frustrating when things are lost on our T's. If my T said that about my loneliness ("you are less alone now, since you're in therapy") I would feel like she was brushing it aside. It is possible that your loneliness is painful for your therapist -- she may be trying to reassure you because it is difficult for her to know how much pain you are in.

Next time you might say, "I really want to reconnect with people and stop feeling so alone." And maybe then she will get it and provide some help?