Sorry to hear you've not enjoyed your first dress shopping experience. You've gone to all that effort and hard work just to come out feeling deflated. My sister had the same thing. Her first shop she couldn't get half of them above her legs! I think when you find the dress you'll just know. I wasn't sure because I didn't have THE reaction or THE feeling but my sister said that my face said it all. Once she had shown me photos of e wearing my dress compared to other I knew she was right.
I think it's a good idea for you to go and try on more dresses, especially ones that fit your new current size. After all, how can you tell if it doesn't fit properly anyway?! I started my search in Wed2B (purely because I was hoping to find something not too expensive) and they actually carry most of their designs in EVERY size. I'd go there and try a few on. Even if you don't love them, you'll be able to try them on properly and really get a feel for what they look like on. Also, be proud of your new figure and what you've achieved!
I actually got my dress from Bellissima in South Woodham Ferrers and I think they carry lots of different sizes so perhaps give them a call. The girls in there are wonderful and many of my friends went there based on word of mouth recommendations.
Good lick in your search - dress shopping is so much fun so I hope you find your dream dress! xx