Divorce Attorney fees

So where to begin. I am in the middle of a divorce, and I what I thought supposed to an amicable divorce has now gone sideways. My soon to be ex-wife has my son, and is now unwilling to let me have him. She has some how been able to afford an attorney so I am trying to hire one as well. The problem is I don't not have the money required to pay the retainer. I don't normally ask for help, but I miss my son and don't want to lose him