Anxiety over labor

I'm getting anxious. Everyone seems to be in a big hurry for me to go into labor, but I'm perfectly happy waiting until the due date! Yesterday we went to the new Cabelo's so I could do some walking...I'm feeling so UNFIT these days. On the way home I had awful shooting "down there" pains. I don't know what you'd call them. I usually have them at night. They don't fit the description of what everyone tells me contractions are like, so I really don't know. They went on for about half an hour, then stopped. I'm finding myself worrying constantly about how Isaac will be. I just watched a thing on autism this morning & got all scared with the "what ifs". I also worry about things like Down Syndrome & things like that. All three of my grandmother's brothers were born deaf and her sister had two mentally retarded children. I keep looking back over the course of my pregnancy hoping that I didn't do anything that would make for anything but a healthy baby. I know I should stop worrying, but it's a pretty hard emotion to turn off.