Congrats on your first game! I really like the variety in character designs here and the art style is very cute and cohesive. I admire you tackling sensitive topics in relation to theme, it's handled with care and written well, and sends out a good message about how you should have people you can confide in rather then trying to take the burden of everyone else's problems at the cost of your own mental health.
I like the ui of the heart breaking, and the screen getting darker to represent the main character's mental health getting effected, although there appears to be some scaling issues with it, I'd suggest changing the stretch mode to canvas items in the project settings to hopefully sort that out.
some music, and sound could elevate the experience and i also think it would be impactful to have some screen shake when you loose a piece of the heart.
Well done, good effort! : )