I think you may be pleasantly surprised. More than any clothing, wedding dresses are cut to be quite flattering, and if you have a good salesperson, they will know what to pull for your shape. Many women I know have been caught off-guard by how nice their wedding dress makes their body look. Also, I don't really recall from my shopping days, but I find it hard to believe that many bridal shops have harsh fluorescent lighting like a department store dressing room would, so that's a plus right there.
Maybe you could go in some shapewear; that could help with the undressing anxiety to a degree and also with the fit of the dress. You're not far off goal, so I think you'll look great. These salespeople have seen so many folks in various shapes and sizes; I would think nothing would surprise them anymore.
Just keep an open mind. You might not look like what you pictured; you might find something totally different that makes you look stunning!
Best wishes for many happy years together!