Dealing with a crazy ex

Currently I am 8 weeks. I found out when I was about 4 weeks and 4 days. First person I told was my ex because hes the only person that I have been with in the last 6 months.

At this point I am honestly regretting telling him. A few days after I told him, we tried to make things work. Mind you we had been broken up for a week and a half before this because of him getting aggressive towards my older twins. But needless to say us making things work has last less than a week when he decided to smash his head into the doors and windows on my car and punch my car and kick the tires all while my children were in the car. All because i asked him why he spent $80 at The strip club when we were daTing The first time. (No damage was done to the car).

Fast forward a week, after me telling him that I didn't want him contacting me until I contacted him because i need to calm down and feel safer after what he did. Hes been blowing up my phone acting nice one minute and like a complete psycho the next minute. When I ask him what he wants all he can keep saying is to talk about the child. Like he won't say more than that even when I ask him what about the child he would like to talk about. He called cps because I wouldn't talk to him in the beginning. Saying that my dad was abusing my other two kids when my parents dont even live with us. Nor have the spent the night with them in a while. He keeps saying that he is going to show up at my house or the hospital when I have the baby because I am to the point that I am scared for my unborn child's life and what he would actually do if I said something or did something that he that was wrong.

What should I do? Should I get a restraining order against him and not allow him around the for its safety? I have security cameras around my house so he hasn't showed up yet plus he doesn't have a car. Can he come after me for not letting him see the baby even if hes not on the birth certificate?

P.s. I also found out last night that he tried to hook up with my best friend even though shes seeing someone else .