The problem between my friend and I..?

My friend & I have been good friends since we're in the middle school for only 1 year. This is the 2nd year of me in the middle school and we're still studying in the same class. I've been really harsh to her last year as she always thinks negative & i think positively. Whenever something happens, she will be very panic and started to fret about it but not to think of how to solve that problem. Now, I started to dislike her personality which i've disliked since year 1 in middle school. Sometimes, I think she's kind of treating me as her puppet as she's scare that she doesn't have friends. She doesn't wait for me even in the library, after school or whatever time only waits for me when she needs me. When she saw her sister, she will run away without saying a goodbye. & well, she's kind of selfish. She doesn't like treating people and not even me who treated her so many times. How am i going to face her? I started hating her more than the words i can say. And am i sensitive or..?