My last period started 08/10/11 and ended 08/16/11. I have not had a period since. I have taken test that all come back positive. I am having lower abdomal and back pain. What could be wrong with me?

So you are saying that you had a positive pregnancy test, correct? Your first step in that situation is to make an appointment with your OB/GYN. You need to start having regular doctors visits. It is also a good decision to visit different doctors consulting your birth plan to see which doctor you like best. Pregancy causes cramping in your lower abs and back. This is nothing to be worried about but you still need to get yourself to the doctor so that you can start preparing... the OB/GYN will be able to tell you when cramps start meaning something is wrong and when they are normal in your body.