It is understandable your family hating him. They want the best for you and love you.
It is up to you what you do regarding your pregnancy but be totally aware its going to be you alone in this. His relationship is with cocaine not you. He probably did want a family with you but he chose the cocaine. Having a baby will not focus on him getting off the drugs. He should have got off them for you. You should not be second to his unborn baby.
You do deserve better, no one should come second to cocaine.