Doing art project for school on personal identity but I'm afraid to reveal it?

I have a lot of anxiety. I have a lot of deep, confusing feelings that I want to get out, but I always block myself off and don't show any of it. Today we were brainstorming with explosion charts or whatever, and I didn't write a single thing down. Some of my other friends have similar feelings but they were able to put their feelings down on paper to a degree. Why can't I do it? I had things to write, but I was too afraid to put them down because I am afraid for other people to know. I don't know what I'm going to do for my final piece. We have to explain the meaning behind it and once again I'm afraid of that. Why can't I do it if my friends with similar problems are able to? How can I possibly do this without having to explain myself properly? Or how can I get over it?