Was in a car wreck and I had no insurance and got considered "at fault"?

There was no statement taken from me at the time of the accident and there were 2 cars ahead of me on the expressway. A car behind me hit me and drove off. It caused my car to hit the car infront of me, and caused that car to hit the car infront of it. There were no witnesses so I'm put at fault because I was the last car. Now the car I hits insurance company is suing me for $6000. I can't even afford to do $50 a month for that right now. If I had that kind of money I would have paid my freakin car insurance. I'm a single young lady that's getting my paycheck garnished for student loans and I only make $10 per hour. I have rent, a car payment, and so many other bills. I've tried gettting a second job and I'm either over qualified or under qualified or they can't work with my day job. It's lose lose here. WHAT CAN I DO!? HELP!!!!