It depends how old you are and if you want to keep the baby.
Because one thing is sure, the father of the baby will not leave his girl friend and his daughter.
So if you ask me, you got only 2 choices. If you are old enough, you can keep the child, raise the child as a single mother and ask monthly alimony from the father.
And the 2nd choice wold be to have an abortion, and forget about this guy and continue to live your live.
If your are still young, talk to your parents, ask them about advise, don't be scared to to talk to your parents. My mother had me at 16 and she is no regrets about having me or about talking to my grandmother about me.