Cutting family off! Am I wrong? Please take time to read

I'm the youngest of 5 kids. Our parents are deceased. My two sisters are in bad living situations. My oldest sister got 6 kids. The oldest is in foster care. The second oldest lives with his dad family. Which is not a good stable environment for him. My oldest sister is 32. She only had a job when she was 17. She got the first paycheck and quit. Never worked since. She dropped outta high school. She get a 700 dollar check for one of her kids. She sale her Ebt. That's how she been getting by. Living from house to house with other people. Or getting apartment and not living in it long because she can't afford it. My middle sister is just in a tough situation. She married a guy and got pregnant. Quit her job and they moved across town. He beat her. They lost everything and separated. My situation is that I moved to another state. I have one child. My own apartment, job, and car. So they both look for me to help. I have helped them in the past. I'm at the point where I'm tired. My middle sister is mean and don't like to help nobody but herself. When I lived in the same state as them I was having trouble finding family to watch my son while I work. My oldest sister lights was off so I wouldn't let my son go there. My middle sister refused even if I agreed to pay her and work overnight. My son went to kindergarten and he begin to act out. It was so bad tip the point I had to put him in a psychiatric hospital. They didn't offer support or concern. It hurted me deeply. I moved out of town to get away and make Better for me and my son. We are doing good. His behavior is better. Now they both are going through rough times and I don't want to be weighed down with there problems. I admit that it's a lot of gossiping going on among us. And I'm just tired of it all so I'm cutting them off. Am I wrong? FYI my two older brothers have their own problems and my middle sister live with him and his family in a two bed room apartment. He is ready to put them out. She got back 4000 in taxes and bought shoes and clothes. She owe rent and light.