I have a lot going on right now with my extended family. I mean, a LOT. Things are changing constantly and dramatically with them. I have to be sweet and patient for my kids and put on a positive face for my peers and so my poor, darling hubby has been getting his rear chewed for a couple weeks now. I knew I was off and he sure knew it too but I finally just melted down this weekend and before I knew it I was sobbing in his arms pouring out all the hundreds of little things that were kicking around in the back of my mind that didn't relate to our specific day to day but they were affecting me (my parents are getting a divorce, my uncle died, that sort of thing...)
I'm a grown woman well aware of how to discuss my feelings and deal with confrontation and I simply was not able to explain to my partner all the things I'd been feeling. I don't know exactly how to offer advice, but perhaps your daughter is experiencing a similar situation. At, what 9? 10? everything is changing. Is she a grown up, can she still be a little girl? She doesn't know right now.
I was lashing out at my husband because he was supposed to be my safe place and every little thing he did that made my day even an itty bit harder was like a huge emotional blow for me until I realized what was causing my emotions. I know "rewarding" her might be the last thing you feel like doing, but if you can, maybe just do something really wonderful for her that lets her know how much you're just crazy about her for who she is. Not really a "grown up" thing but just something amazing just for her.
You haven't failed her, and maybe something else is going on but it sounds to me like she's just trying to figure out the world and it's pretty overwhelming. She needs some time and a safe place to work it all out. I used my dollhouse for that sort of thing until I was almost 14 years old. (But, of course, I didn't tell anyone because that was so uncool.)