I'm so sorry you feel that way! I can absolutely understand what you've written as I feel the same. I've always had confidence issues but since wedding planning started my insecurities got so much worse and turned into body dysmorphia. I'm struggling with it so I can't be too much of help but its great that you already see a therapist. you could try taking care of you and respect your personal limits during this planning stage. I think the more stressed one is the worse the insecurities get. I know you can't just start thinking of yourself as attractive (I wish) but maybe find a photographer you like so you can trust in the photographers capability to make you look as amazing as possible (I mean, thats what they do). Also try thinking about you like you would about a friend or even a stranger on their wedding day. I've never looked at a bridal couples picture and thought "oh god her teeth are bad...the hair is too thin...fuck,THAT dress", so why should I think about me that way? I'm sure you'll look lovely on your wedding day because you will show genuine emotions and your groom and guests will beam at you! I wish you good look, it absolutely sucks hating the way you look :(