Please help if you know this manga!

I read this manga a couple of days ago and I think it was a shoujo (terrible memory) manga and it is about a girl who is always overshadowed by her (step?) sister and (step?) mother. Her sister wants to become the star in a movie and later finds out that it was supposed to be an open audition but because to many of the male leads fans came, it became a private audition that only those who have a letter could go to (the director's crew handed them out to the major acting companies). She always went there to try out, but instead of the lead role, she went to try out to become one of the troublesome actresses' manager. She succeeds and goes home. Later, someone calls saying that her sister is drunk and that she needed to go pick her up. It ended up that the sister tricked her in order to pay off her debt of drugs and get an acceptance letter into the audition. Someone she knows (I forgot who) saves her... That's all I remember. I also know that it had very few chapters... Even if you can't remember but try your best to help, thank you very much for trying. >.<