Debbie, last year, I bought the exact same slippers that I've been wearing for years, and now they no longer fit. Since I've been buying a couple of pairs a year for several years and they always fit right out of the box, I'm sure that the company has changed them.
I've been wearing the same tennis shoes (literally the same pair) for several years because the company has stopped making them, and I can't find any others that don't hurt. I keep changing the arch pad inside and sewing up holes, but eventually I'm going to have to find something. I dread it soooo much!
This summer I had minor toe surgery, and I couldn't wear a closed toe shoe. We were going to Disney World (we had had it planned for a long time, and the toe surgery was unexpected), and I tried like crazy to find a good, comfy sandal. I bet I ordered 7-8 different pairs to try, but they all hurt. I ended up wearing my old trusty tennies and wrapping my toe like crazy.
I don't have any advice or suggestions; I can just commiserate with you.
I really think it is super difficult for fibromites to adjust to new shoes or even find shoes that are wearable.
Hugs - Austen