One of C's best friends is getting married 3 weeks after us with a pretty much unlimited budget, they are planning it in 9 months and the bride looks like a bloody page 3 model so as always, I get where you're coming from - but you just have to focus on your life, what you can do to get to where you want to be, and congratulate yourself that you have a strength of character and determination they will never have, and it will serve you well in the future.
Also, one thing being a mum has taught me is that lots of people are like swans...you think they have it easy, they are gliding serenely on the surface.....but underneath their little legs are paddling away like billio! Loads of people I thought had their parenting/life shit together were struggling just as much as I was when we had an honest chat about it. So don't be jealous, the likelihood is they have their own problems/insecurities etc. and loads of people I thought were financially much better off than us, in fact aren't. Another friend of C's and his wife live in the most enormous brand new 4 bed house, everyone thought they were doing really well financially, but it turns out they are in debt up to their eyeballs and spend every month juggling credit cards just to afford the food shopping.
Weekend away sounds fab, enjoy and forget about everyone else.
I'm sure you have, but have you tried Asos? I got some that look very similar to the TKMaxx ones, just a little less sparkly but still with the block heel and round front and they were super easy to walk in when they arrived!