I live in Oregon and so I can't recommend a lawyer. I can suggest that you talk to someone at juvenile court. They work with lawyers everyday and some of them will be in family law.
Another idea is to call one of those attorney's. Tell them that you'd like to hire them but you don't have enough money. Ask for a referral to one who considerably charges less.
I agree that you shouldn't let your ex have unsupervised visits until you have an attorney. He can advise you best. I'm guessing he'll immediately go to court for an interim order but I don't know for sure. Before you get a lawyer I would advise that all visits be supervised. If possible by an emotionally strong person and if possible a "disinterested" person. Someone who doesn't feel a need to take sides. By emotionally strong, I mean someone who strongly believes that you should have custody and who won't succomb to your ex's emotions. That means that they are able to return your son to you while maintaining a non-threatening attitude with your ex. No fighting.
I wish you the best, H.. This is a long difficult road that you are traveling but it will end eventually. Find someone that you can vent and/or talk with to help you keep your sanity.