I left my fiancé a month ago, after we had a fight and he reached into my car (windows were down) to take my keys out of the ignition. I was leaving because the fight was escalating and I felt I should leave to let him cool down. When I asked for my keys back, he threw them at me and they hit me in the face (I ended up with a bruise over my eye and a few scratches around my eye). I put my keys in the ignition and drove off. He then proceeded to follow me on his motorcycle. I drove to the highway because my ex only has his M1 (which means legally he can't drive on the highway). But that didn't stop him. While we were driving on the highway he was trying to cut me off, he was driving beside me in the same lane and banging on my window. Finally when I wouldn't open my window or get off the highway he started kicking my mirror. Finally after an hour, I told him if he didn't stop I'd call the cops. That's when he finally left. 

I'm scared I won't get custody because I didn't report this to the police. I only told his mum and my friend. But I just don't trust him with this child. 

If anyone can help give me more information about what my next steps should be, I would really appreciate it.