<human>: I'm really sorry if this comes out as choppy and with bad english, as it's not my first language and I haven't really thought of how to explain the situation.

My sister has been bullied at school for a long, long time. I don't remember when it startet, but it was in second, maybe third grade, and it continued through to seventh grade before the teachers reacted and in year eight she was promised to not be in the same class as the worst bullies. 

Even thou she's not bullied as much now as before (she starts ninth grade soon), it happens now and then. She's a litte sore form past experiences and takes critic and crass comments on fast. 
The positive thing about her getting a different class, and being a little separated from the worst people is that she has gotten a pretty good friend group that seems to fit together good and take care of each other. 

Even if things has gotten better, the psychological effects of the past bullying has begun to come. We have found diary pieces, or rather she showed my mom, where it stood that she thinks it her fault that she was bullied, and it was her fault that our cat recently died. That everything was because she did all the wrong things. This was so heartbreaking to read. She also has a tendency to "explode" in rage periodically because of small things and usually says things like she's always doing things wrong and is fat/ugly/not good enough. It takes time to turn her around, but it's possible and she's a cheerful person the rest of the time. 

I know that therapy is the best option for her, and we have contacted the youth therapy people where I live. I'm just lost on what I can do for her. I want to help her, and for her to feel that she doesn't need to be anything other than what she is. I try to encourage her to don't take what these people say to hart and to just be herself, but I'm afraid that I'm not doing it enough. I really love her and want the best for her, but I'm not sure what to do..

Could you distill the essence of the text into 1-3 sentences?
<bot>: My sister is struggling after being bullied for a long time. I'm not sure how to help her/tell her she is good enough