I’ve lost 4 stone and not one person has noticed

[Lilyflame]

Just that really
aibu to feel a bit miffed.

They absolutely have noticed, especially those who have seen you out of a winter jacket. People just don’t comment now imo (which is a good thing) other than if they are pre war adults (so late 80s+ now) or your very best friend.

You need to work on your own insecurities—it's clear you're asking others for validation, and that's not great. You should focus on losing weight for yourself, not just for others to comment on it. It sounds like you're not happy with yourself, and that's where the real change needs to start.