So this has been sitting in my favourites for a while and I never bothered with a review. Time to change that!
In short, I think this is beautiful. I especially love that the ugly truth bubble gets bigger by absorbing the happy ones. Experiencing something terrible can make it harder to appreciate the joys you have, or can even make you see them in a darker light (is that an oxymoron?), twisting the once happy memories into something painful. Trying to repress sad feelings just made things worse. That's what I think of the bubble absorbing the other ones, at least.
The way you show this abstract concept is great, and I love it. I like the colours and the music as well, I find myself humming it sometimes even now. While the character design is cute, the style isn't overly childish and the dreamy environment fits the theme well, I think. Great job!