I remember feeling the same way as you when I first went. I had no idea how to articulate my problems beyond "something doesn't feel right." T asked me lots of questions in the first few sessions, and left lots of room for silences so I could find what I needed to say.

Ts are used to how strange it feels at first. Roll with it; whatever you say (or don't) is okay. When you're ready to dig deep, you will.