Social worker fired unjustly?

I was recently terminated from my 2 year position as a social worker at a non-profit. My official letter stated that my "position was being eliminated". When I asked the HR director for a reason, he said that it was because my documentation was behind and that was a firing offense. Every social worker there is behind on their documentation. I could tell he was not comfortable terminating me because I'm a good social worker. The week before, I had challenged the Director of Social Services on some issues in our department and even offered solutions on how to fix them. He did not appreciate my input and I knew at that moment he was going to get back at me in some way. He was off the next two days. His next day back, I was terminated. Before this, he had always said I was one of the best social workers he had ever seen. I'm not even sure why I was fired. I loved my job and my clients. This was personal. I printed out all emails from my supervisor before I left because I felt like something was going on. He has said very inappropriate things about our patients. I am not out for revenge but I feel I was unjustly terminated. What can I do? My unemployment starts next week