My feet seem to have shrank! Please, please help

[BubblePopper]

I am going to a wedding in 2 weeks and had got an outfit together that I am comfortable with (which is not an easy ask for me-style & beauty is a new world to me!) I have tried the outfit on and it's all fine except the shoes are falling off my feet!!!
They fit fine when I tried them on. I can't return, they were from a charity shop and my budget will not stretch to a new pair. Nothing else I own goes. I guess I'd tried them on after a LOT of walking and my feet were perhaps swollen but I can't attend this wedding with shoes falling off, I'll break my neck!!!
I'm going to try and link a pic of some similar shoes in the desperate hope that some of you experienced stylish ones will have some ideas/tips.

www.spottymarket.com/product/womens-bola/10515

Were your feet cold when you tried them on again? Might insoles solve the problem?

ah, no, not with that style of shoe, no. Sorry!

maybe sticking a couple of those really thick blister plasters around the ball and sides of your feet to bulk them out a bit, so they stay in the shoe?

Or some of those heel liner things stick in the ball-of-the-foot bit of the shoe?

You need a half insole, like party feet but from homebargains or the pound shop.

Then when the feet swell during the day you can just pop them in your handbag.

not sure those heel liner things would work hopefully the strap bit on the back isn't too wide.
Will look at half insoles fluffy and see what they are and if they'd work.
Thank you for your help