Custody question

My ex and I have a 3 month old baby together and I currently live with him still but plan to move back to my parents which is 5 hours away. I WILL take my son and don't mind how often my ex wants to visit. But he says he will take me to court to take my son away and get custody of him. He plans to use screenshots of us fighting through text to make it seem like I'm not a fit mother. I still use breast milk for my son so I have no idea how my son could even be away from me. Can my ex actually take my son away from me?