Tried Everything with Demanding Child

Naomi, We are attachment parents and I have listened carefully to your advice after I read your book, bought your CD's and read all the questions on your site. I still feel like I am missing something; some magical equation to live peacefully with my three-year old. Since the birth of her brother, she has wanted to breastfeed as often as he does. I reduced her to once a day at naptime which was working out for me (and she accepted it since I would cheerfully give it to her once a day even if it was really painful since I knew it was only once a day and not ten times a day). When she got a fever and later UTI, I let her have it all the time. Now she wants it all the time.

Now that I let her have it when she requests it, she seems even more demanding, even more intense and seems to have more rage inside her. She isn't tantruming as much because she can have the breast but she is very emotionally expressive and complains/whines/rages even when I calmly let her know that I need a moment (to pee, wash my hands etc). She will push her brother and try to remove him from the wrap so that she can nurse. I try not to "protect" him from her (her pushing actually makes him laugh and giggle) and I do try to spend time with her when he is sleeping but I cannot make up for the attention she received before he was born. What am I missing?