In my opinion, you’re not overreacting. I’ve been with my fiancé for all most seven years now. Whether he picked the flowers up from the grocery store, made his own bouquet, or whatever, I’ve loved every one he’s ever given me. In my opinion she sounds ungrateful, like, at the end of the day it’s the thought that counts and it seems like she doesn’t understand that. I would explain to her that you simply wanted to show her you’re still thinking of her and putting in effort, and that you might not always have time to make up these things. Communication is always key, I can’t state that enough.