child in different state and need to change child plan

This happend in SC about 8 years ago. I had a grilfriend who said she could not get pregnant. However, she got pregnant after we broke up and becuase I still loved her I asked her to marry me and take full responsibility of our child. My son was born and I bought her plane ticket to go see her family in CA. She was suppose to be gone for a month but she kept making excuses and did not come back. Three months later, I received some paperwork from the police officer and she put restraining order against me and wanted full custody of our son. I flew to CA but everything was very complicated since we were dealing with two different states. I found out later that she didn't put my name on our son's birth certificate and waited long enough to gain her residency in CA to send me that notice. I was very distressed at that time and felt helpless. English is not my native language and I have very limited knowledge regarding law matters. So I gave my girlfriend what she wanted hoping it will solve some mis-understanding between us as time passed.
Since then, I moved to Seattle,WA and I did not have a job for awhile. So I could not make my child support. My employer received a notice from the child support agency letting them know that they will take $ out from my salary. However, what they take out is too much for what I make. I'm willing to do my part as a father and I feel very bad to my son. However, my ex-grilfriend has no intention to work but to depend on me. What are my rights? - Is this your question? Add additional information