Severe Fear of People and I don't know what to do?

Ok so I have a severe and crippling fear of people. I don't ever leave the house except when I am forced to by my parents. I honestly don't know whats wrong with me. I've been to multiple therapists who assume I have Social Phobia but I don't think I do. My problem isn't really with talking to people its with being around them. If I am around other people or even just one person I have really bad panic attacks. If I'm sitting in the car in a parking lot and I see someone walk by I have a panic attack. They don't even have to be near the car. Even if I don't see the people but I know someone is there like in another room I have panic attacks. I can't talk on the phone for the same reasons. While currently writing this I'm starting to feel the beginning effects of panic attacks. I could just be sitting at home but if I even think about something involving human contact I freak out. I'm at the end of my rope with what to do. While I've gone to therapy I can never last more than 4 sessions before I can't force myself to endure the fear any longer. Every time I go it gets harder not easier. So I can't go to therapy. I'm miserable and it sucks. I can't get a job for the obvious reasons and I can't move out. I'm 20 soon to be 21 and still living with my parents but I need to get out of here but I don't know how. I have no way to make money. While being with my family when around others used to make me a little more comfortable, now Its getting to the point where I don't want to be around my family because I'm becoming more uncomfortable. I don't know whats wrong with me or what to do but I need help and don't know how to get it. So if you can offer suggestions I would seriously appreciate it. I just can't take this and the constant fear anymore.