I just recently had a 'break' from counselling after a year. I felt the same way as you, I hate the feeling of letting people down. Makes me anxious. But I'm really pleased I took the time for myself. It did me good.
Maybe you should go to the session this time, explain how you are feeling with your t. Sometimes when I really dont feel like going, they are more productive. Maybe it might help with the feelings of being overwhelmed and being run down.