#modern au technically

AITA for giving my summer fling a petname?

I (m34) have been calling my hook up (f32) "Colibrí" all summer. It means "hummingbird" in my native language. Anyway, we weren't supposed to do feelings, or nicknames, but as the summer progressed we got closer and closer and I think I might be in love with her?

So, this morning, we had mind-blowing sex (as usual) and afterward she finally asked what "Colibrí" means. I told her, and she FREAKED out on me. Pushed me out of bed and immediately got dressed. Apparently, her brother (who I'd never met – he died about six months ago) also called her "hummingbird."

Obviously, I had no idea. But, she didn't believe me and basically accused me of knowing and calling her that on purpose just to hurt her. That felt really shitty to hear, because, again... I think I love her and I would never do that. But, I was angry and hurt, so I admitted to reading a few pages of her journal and accused her of using me for inspiration for her next romance novel (yes, the sex is that good). 

Then she called things off. 

I know reading her journal was wrong, but I think she really overreacted about the whole "hummingbird" thing. And now I'm worried I'll lose her before we even really began. 

So, reddit tumblr, what do I do? And am I really the asshole?