39 weeks pregnant and dont know what to do about the last name?

im 39 weeks pregnant and single. the father is saying that if i don't give him his last name then he is going for full custody. he said that it is the way of the iwi to have his last name and it cant be broken. but we are not together and i really want him to have my last name so that everyone knows he is mine and that when i have more kids they will all have the same last name. and some of the things he said to me yesterday make me sure that he wants to take my baby away from me as soon as he can so i want to give him my last name and not put his name on the birth certificate so that he can not do that. i don't smoke drugs and i am very against them i don't smoke and i do not drink and i am in a stable healthy environment and he is my number one priority!!! but he still thinks that he can get full custody. i think he thinks that because of all the immature things we have said to each other while angry and all the stupid little arguments we have had as we are only 17 and this was our first serious relationship and we have known each other most of our lives so i think he is going to try and use all of that against me but he is very violent (swears and yells ALOT) and has very bad depression. he used to be addicted to weed and smoking but tells me he has quit. but i don't know if i should believe him or not because he is a lier to. i still love him like crazy which is strange because of the things he is saying to me at the moment but i cant help it. so i asked him if we could have a fresh start so we can get along for baby and he said only if he can have a say in babyz name etc but he hasn't been around much during the pregnancy and never asked how he is or anything and his reason is because hedidn'tt want to talk to me which i think is a pathetic reason so idon'tt feel like he should get a say. is that fair??? im scared that if idon'tt do what he wants and give him a say that he will go back to nottalkingg to me and try and take my baby away from me. what should i do???