Help Needed in Custody Battle

I’ve been in a custody battle for over two years. My child’s father is a wonderful father, but he is trying to have full custody of our child and give me very limited access to him.  I have fought legally with every dollar I have made in the past two years, but I have finally hit a financial wall. 
I have paid out of pocket for drug testing and background checks and everything that has been asked of me.
My child’s father hired a guardian to speak on my sons behalf- This guardian now wants me to go out of pocket to the tune of $5000 for a Psychological Evaluation to prove I am a decent parent. I love my son very much, and if I do not get this evaluation I could lose him.
Any amount you can give is appreciated. If you can’t give, please just SHARE my post.
Thank you so much.