Their answer to a present was just a thanks back, now I don't know what to do.

So basically the title, I made a donation on their name as a job promotion congratulations. The foundation emails them that a donation has been made on their behalf by me, that's how it works. I also added a note at the end to make sure I am keeping things professional. I didn't buy anything because I don't know if they kind of think I'm into them so didn't want to take any risks. Do you know what their email to me was?? "Hey, I should be the one who's thanking. That's thoughtful of you. Best, x". I don't know why I got so disappointed over it. I guess being delusional breaks your heart more than a normal situation can at times like this. I got used to imagining and daydreaming about them so much that I expected a warmer response. I always put the fact that they are nice to everyone and not just me at the back of my mind. Who knows who they are chatting with and who gets to enjoy their company. Ugh, I hate everything. There's so little that I wouldn't do just to be in their life. I wish I was enough. I feel like there is no meaning in life. I wish I had the guts to do it, at least they would pay attention to that.

I played their response over and over in my mind all day long. I don't know why it makes me feel so empty that I feel like a part of me is missing.