Hey, this happens me too sometimes. What about taking a few minutes to think of the things you like about therapy, the nice things your therapist has said to you and about some of the really good sessions you have had, that way you will feel more motivated to going to you session.

Then sit down and even just make bullet points about what you would like to talk about.
Sometimes I dont prepare for a session and find I can talk away fine and sometimes I prepare and still find talking hard...its not easy but just do your best and remember your going to see someone who cares about you

we are here for you for when you get back as well!