You will face a very uphill battle if you try to do this without an attorney. Custody litigation is complex, and there are numerous points of law that presumably you will not have at your disposal. Contact the county bar association to see if they have attorneys who will assist either pro bono or for a reduced fee.
It depends on the facts of the case, but not having a lawyer is a horrible idea.
My standard disclaimer: I am not offering legal advice or services, assume all of my advice is completely incorrect, assume I do not know the law in your state and assume that I am just making suggestions for starting points for when you do speak with an attorney. Do NOT rely on anything I write and contact a lawyer in your area immediately after reading my posting.