I am 18 years old with a baby on the way

Me and the father of my child have been dating for a year. We had a big argument and at first he wanted to work it out. But with time he started asking others and they told him to leave me.Now he wants me to wait on him to mature. He wants to talk to other people. Then come back in four years. He doesn't want to deal with me while I'm pregnant. He doesn't take me to the doctor or anything. I feel alone. How do I handle this situation?