Dear Claret,
I guess it's part of growing up, this relationship with your mother. I expect you thought, as I once did, in the same situation, that you were already grown up, but if you care about your mother,and she has dementia, there is always some more growing up to be done. :(

You have a mother, Claret. She ain't the one you remember, and she ain't the one she ought to be, but she is still your mother.

You were quite right not to remind her of your birthday.

There comes a time when that is too much to ask. She has loved you for, ooh, I don't know how many years and it's time to give her a break from the burden of remembering birthdays.(Oh, and Christmas too!)

You know she loved you, when she was pre-dementia, and she certainly will continue to need you. It's just going to be a bit more difficult to relate to her if you expect her to be her former self.

If going clothes shopping is going to be stressful, then don't do it. If she doesn't enjoy clothes-shopping and you feel hurt by it, then don't put yourself through it. Get clothes for her by yourself. Keep the receipts and take things back if she doesn't like them. Or maybe take a friend with you to lighten the load?

I'm sorry you have had a miserable birthday. I hope things pick up for you. Of course you must have a break if you need one. Every carer needs breaks. It's not selfish to acknowledge that, it's plain sensible. That's how most people carry on caring.
You have to take care of yourself, Claret, as I am sure a thousand TPers will tell you, in the fullness of time. Kind regards Deborah