Awww....I'm sorry it was a bad experience. What I found helpful, when I was looking for dresses, I would see online if the dress is offered in plus size (that way you don't ask for it and they give you a small size to try on).
My dress was a Mori Lee dress and she has some beautiful gowns in plus size. I also tried on some Alfred Angelo designs and those were nice too.
Definitely try to check out Trudy's Bridal....and ask for Tammy. I referred my co-worker to her and she loves her. Tammy really made me feel gorgeous even though I was intimidated by the size 2 brides around me. The dress I chose
wasn't my original choice, it was one that Tammy happened to pull along with the dresses I specifically asked for. I hope it goes well!