Hi Jackie, Welcome to DV.
Thats quite a descriptive dream you have posted there. There are a few things you have mentioned in your dreams which i can relate too. The part where you explain that "you are trying to run away, but you cant" I have had this occur several times in my dreams also. It's also when im trying to run away from something/someone.
I dont really have any sort of explanation for reasons why this happens. Only thing i can suggest is; If you can learn teqniques, and how to control your dreams you could use this as a way of finding out what it is your actually running from and why. Once you have done this you may be able to conquer this problem.
I have always been able to wake myself up, therefore i used that as a way of dealing with it. However that didn't solve the problem, just prolonged it. So if you want to learn, and when you do - you will be able to stop running, turn around and face the problem.
I think your second dream, its basically because of your worry of becoming pregnant.

Sorry i haven't been much help, There are alot of nice people on this forum and people who know alot more about the mind, dreaming than me . hopefully they will be more of help.