What can I do to fight for my baby boy?

The father of my 1 year old son is determined to get full custody of our child. As far a mom, I believe that I'm a good mother but I am worried because I'm not sure if the judge will find me fit enough and will give him custody of our son. I have 4 other kids and I live under section 8. My rent is free. I pay light and water. I am an unemployed/college student and live off one of a check I receive for one of my other kids $733 monthly and my 1 year olds SSA check of $67.00. The father of 1 year old has called DCF on me multiple times to try and get my kids taken. Some were false accusations of me hitting my kids and neglecting them, false accusations of drug abuse (DCF drug tested me 2 times and of course I was negative. I hate drugs), also called DCF because I had a clogged toilet in my house for a few weeks. It was a major job for the toilet to be fixed and I couldn't afford it. The owner wouldn't help. My DCF case had been open for almost 9 months due to the previous domestic violence incident that occurred when he hit me. I am afraid those cases will be used against me in the custody battle for my 1 year old. The father has a history with me of domestic violence. I had gotten a restraining order on but then I got him to complete a Batterer's program and parenting education program. I had dropped his restraining order back then in hopes for things to take a turn for the better for our son. Now, I'm concerned that he may use the programs he completed in a way to take custody of my baby boy. Another concern that I have is a few times I didn't clean my house. He had taken pictures secretly and said he would use them against me during an argument when he told me he wanted to get full custody of our 1 year old son. Will I lose my baby boy?