You need to leave early for "an appointment" or for "personal reasons", you don't need to explain. Do go. It may help, it may not, but you can't know if you don't go, and your T is taking the time to give you support and asking you to do this thing for yourself. You don't have to "share" much, you don't have to have any expectations. Just go even though it is hard to do. (you are spending a lot of energy talking yourself out of it)....anyway, that is my advice---advice from someone who knows it is usually better if you DO even if you have all kinds of "reasons" not to