I dont know if my German Shepard is pregnant

Question
I'm only a teenager and I have a german shepard who is about 2 yrs old. Her ribs look like they're expanding and she has been much calmer than usual. she was in heat within the last few months and when she was, there was a male dog around our house. She got lose one day but not for very long and I just wanted to know if there are any warning symptoms that I would be able to use to see if she is pregnant.

Answer
Chances are good that she is. If she is putting on weight has increased appetite, and her nipples are larger or more pronounced than normal she probably is. HOwever you said she had a normal heat within the last few months. A canine pregnancy lasts nine weeks, if it's been longer than nine weeks, you're safe :)
Cindi