My ex is trying everything she can to keep my son from me, can anyone whose been through this give me advice?

First she got a restraining order claiming she is afraid of me, then when we went to court she could not prove any of her allegations, so the judge gave me unsupervised visits and ordered both of us to go to parenting classes. We go back in a few weeks and the judge said weekends and overnights will be on the table. He wants our son to have both of us in his life. He did keep a restraining order for his mother and myself, so that we can only communicate about our son, which is good because I do not want to talk to her about anything else. There is no criminal charges related to the restraining order. I have never been, arrested, accused, or charged with any. The judge sees that she and I cannot get along, so he gave us a year apart from communicating. Now she called a Social worker who interviewed both of us and our son (he is 5). The Social Worker called me today claiming that a report had been made that my son came home with marks on his elbow and butt after our visit and that he said, "It's mine and Daddy's secret". He tripped on the stairs and received a very minor cut that did not even bleed. I cleaned it and put Neosporin and a Band-Aid. The Social Worker is interviewing our son again and I am awaiting her call back. The cops were never called through out our eight years together. she never made mention of any abuse to her or our son until she ended our relationship. I have no criminal record. All I want is to be a part of our son's life and his mother is trying everything she can to show I am unfit.