Why does Jeannette just sit and wait for the family to return after she falls out of the car? Why doesn't she seek help?

From the text:

The little town behind me was quiet, and there were no other cars on the road. I started crying, but that only made me feel more sore. I got up and began to walk back toward the houses, and then I decided that if Mom and Dad did come for me, they wouldn't be able to find me, so I returned to the railroad tracks and sat down again.