My Younger Sister Disrespects Me Alot

Haven't done this before, but I want to know your honest, experienced and well thought out opinions. I'm really depressed but I won't take Snipper (that devil is a liar). If you don't have anything serious and reasonable to say, please, just read comments (I know as e dey be for here, sometimes).

Here is my story.

My younger sister who is staying with me disrespects me alot, and she doesn't take my advice. My parents stay very far away and I feel responsible for her. It frustrates me whenever I tell her something and she will wait to do it at her own time or not do it at all. She even sometimes abuses me indirectly.

She is 19, came to stay with me last year November, for a Predegree program, after staying at home for two years without admission. After the first semester of her program, her result was released and it was very disappointing. She made 51% in only one course of four courses, while others are below that.

To be honest, I felt I failed in my responsibilities of giving her the right counsel, motivating her, and all that. All she does is press her phone all night long, that's if she isn't watching a movie with her phone. She'll sleep and wake up the next morning by 8 or 9am.

Recently, there's this guy who happens to be my late landlord's first son in the compound where we stay that she has been spending too much time with in dark corners and I can tell in my gut that he's up to no good. He doesn't go to work, school, church, nowhere.

He just seats at home all day, smoking weed and any other smokable substance he can lay his hands on. Sometimes, his friends come around and they smoke and play PES 2011 on a laptop. Lest I forget, he's also a cultist. He has tried on several occasions to make me a yahoo boy, but I had to consciously refuse.

About a week ago, this guy asked her to cook indomie for him, and she did, using our gas, without telling me. This got me really up set. I had to take several deep breaths. I calmed down and allowed her finish. After she was done, I asked her to seat down and we started talking. While we were talking, she started responding rudely to me.

This made me hit her for the first time in 19 years (I hate hitting them). To my utmost surprise, she hit me back. That singular act made her receive a very hard beating that she sustained lots of injuries. She immediately called home and my parents where now shouting at me on phone.

My dad came the next day and said lots of things. My mom said lots of things on phone which just piss me off the more, called me all sought of names. Said I shouldn't allow the devil that is controlling take me close to my sister.

Right now, I hate all of them. My dad, mum, and sister. If I was financially buoyant enough, I would have moved out of this house. I feel really depressed, being having nightmares and I so much hate the fact that am still living here.

Thanks for taking your time to read out my write up