What can I be charged with?

I was pulled over for a moving violation (Bogus). I have been taking on a mission of helping people get back on track in life and the young man in the car with me was one of many. He has a lot of diagnoses. I could not find my wallet and when I opened my purse there was a baggy and the officer asked, next thing the car is being searched. I knew that they were not mine and I joked and said "could be my kids!". My son was not there and I knew if I said I believed that Michael, my passenger put those items in my purse, he would spin out and cause a scene! He admitted to it later. Michael no longer lives here because I was in over my head with him and cannot help him. It's documented that I myself called the police to my home several times because he was in a spin out! He is currently stalking me and all windows and doors stay locked. I have never been in trouble and I'm 53 years old! I know I am not guilty so I forgo the fine and going to court. What will happen, will they believe hearsay after I did not say anything then and passed blame to myself and my son? What are the possible legal outcomes? Court date is September 10th. I can't afford a lawyer and make too much to get a public defender! Any suggestions?