Is it normal to want to leave my family behind?

I'm not sure, but I think my family is causing me more harm than good. I'm pretty sure that they are verbally abusing me and holding me back from growing. I have tried to ignore their behavior. I have tried to tell them how I wish to be treated. I have explored the possibility that I was the one with the behavior problems, and not them. I am slowly and rationally debating on weather I should move far away from them in order to better take care of my needs which are currently not being met.
I am very confused on many levels. I do not know if I am capable of surviving without them. My family has developed a dysfunctional pattern that I have been trying to cope with for a long time now, and I think my breaking point is fast approaching.
The main thing that is stopping me from leaving is money. I have never been able, or possibly willing, to earn a descent living on my own. (The reason why I describe it this way is because I can not decide if my financial shortcomings are solely my fault, or if my family has prevented me from growing)
I am financially dependent on one family member. I am thinking about getting a job to save up enough money to make a clean break, but the current situation in my family is becoming way too much for me to handle. The longer I stay, the more I get sucked in to the system that I believe is hurting me.
This plan to leave my family is a brand new idea that has never seemed like a possibility until very recently, so part of this post has to do with processing the idea that this decision will dramatically change my life forever.
When do you know it's time to leave your family?