Should I feel bad?

So my husband's little brothers gf/fiance/whatever seems to always want my life, she never really liked me bc we are very different though and I tried to ignore all the crap she has put me through. Now making a list of everything she has done might be petty (and long) so I'm not gonna do that... Though there are a couple things that are not only messing with my personal life, but now my work life. Early this year she was trying to get a job where I worked, I was a vet tech assistant, I got the job bc of the long list of experience I have with animals. In two years I was going to be bumped up to an actual vet tech.. and she wanted to be a math teacher until I told her those future plans of mine, she then changed her mind and decided to want to sign up at a college to be a vet tech and eventually an actual veterinarian. I got a little upset but I got over it and decided to change my life goal again.. So I changed jobs and started cleaning hotel rooms (she wanted that job too) then I left bc a grooming and boarding facility was looking to hire me (my current job) now I've been here for a while and of course this girl is begging me for a job, I was warning her saying that they don't hire inexperienced people and the job is a lot of work. Anyways, she got fired from party City and I felt really bad bc she wouldn't have money to get my brother in law a bday gift soon. I talked to a ton of people at my job and they said she can be a temp and we'll see how she does. Now I see this girl who has put me through hell in the past at my job and at home... long story shortish.. everyone up at my job hates her and I feel bad bc I helped her get there. She has been there for under a week and not only is she acting like she knows everything already which is annoying everyone she has already told them lies, and crazy stories about her getting raped, trying to trick my brother inlaw into having a baby with her, and telling them personal things about my husband and I, etc... She doesn't realize how much she gives away and everyone thinks she's insane.... I feel bad for her but it's starting to get overwhelming.

UPDATES- besides this (and probably 20 other things) the main reason she and I don't have the best relationship is bc the first things she every said to me were that I wear a lb. of makeup and then cried to my mil when I got engaged, then asked to get engaged 6 days after me... of course I'm married into the family now and everyone in this family still sees she and I as equal...