I guess my question to your mum would be "Is there anything invalid about your daughter wanting that?" (Spoiler: No, there isn't.)
You have really suffered. You've endured a very hard and scary experience that most people never have to deal with, and now, having come through it, you would like to celebrate the fact that that time is now over. Looking back on past hard times and loss and recognising that you are in a different place now is part of processing traumatic experiences and moving on.
There is nothing wrong with hoping that the people who are part of your everyday life (friends, colleagues, family) will recognise the reality of what you've been through and empathise with it. And most people will not think negatively about that at all.
Often people who get defensive or aggressive about others hoping for empathy (like your mother does) actually feel that they have never received enough care and empathy for the hurts they have suffered in life, so resent anyone else getting any. This is called a 'victim mindset'. (You do not appear to suffer from a victim mindset, BTW.)
It’s a picture of a pink teddy bear, pink ribbons and the word “survivor” on it. It brings me great comfort. When my colleagues look at it do they really think ‘that one is only looking for sympathy'
I think it says a lot that you have done something that is a regular form of comfort to yourself. It sounds like you have recognised you won't get comfort from the people who you might ordinarily expect to provide it, so you have created a way to provide it for yourself.
You should be proud of yourself and your own strength. I'm on the other side of the world from you, but will think of you while I'm eating my lunch and cheer your survival.