How to have natural birth?

Now 39 weeks 3 days. my first born child is Induced, and this second I have no idea. doctor say NAtural birth. But I have cramp and backache. I can't sleep every night. I don't have any spotting nor discharge. I'm so worry.... I wanted a natural birth. I'm so scare at night I will labor as my hub works at night. I get so easy tired in the morning.