I'm on my 3rd cycle of DBT. I've found that the other modules: Core skills, (mindfulness), Emotion Regulation, and Distress Tolerance have been more helpful to me than the Interpersonal Skills Module. Have you done those yet?
DBT isn't the kind of group where you're going to learn how to make friends, though. Do you have a T who suggested DBT to you? Why? It sounds like you're expecting to get something from it that's not part of the course.

Do you fill out diary cards? Maybe you can use those to help you with actual relationships.