I also have a tendency to feel weird / awkward / and even guilty when I stand up for myself. You did the right thing though. And I think you were given a great compliment by your boss as well. Your coworkers probably changed their behavior because they were talked to. And yes, they need to change (and they needed to be talked to) because they sound like a bunch of immature jerks. I don't think you overreacted. You deserve to be treated well and with respect. At your job, in therapy, with your peers, everywhere. You deserve to be treated with respect. When we are not treated well, it is stressful, it is dehumanizing. It sucks. You deserve to be treated well.

I second TravelingLady's question. Do you think you might go back to therapy?