Thanks for your replies. It's actually helped me a lot by just typing all of this as it's not something I've been able to talk about for years.
This is not the exact name but a similar kind of thing and went something like this:
Announced name as Ella Catherine (Catherine one of my middle names).
Fely very hormonal and confused/fuzzy, wobbled after two weeks and changed to Ava Catherine.
Registered as something like Ava Jane, then obsessed because thought it was too short.
PND got worse, obsessed about it for months and then changed middle name so name became something like Ava Olivia.
Then followed years of obsessing/shame/embarrasment about it all and wished I had stuck with the original name. Plus thinking about all of the names I should have called her Eliza/Elizabeth, or Harriet or Beatrice or Catherine/Kate, or quirky like Polly, Betty, Sadie etc....
So when I hear the name Olivia it makes me upset as it brings it all back. I don't even think she remembers it's her mn.
So if I added Catherine back it would be a mouthful - Ava Olivia Catherine.
I sound like a crazy person!...which I'm not usually, honest....that's why I don't understand why I can't just let it go.
My other DC has a popular but classic name, think James William, which I am proud of.