Possible Pregnancy: Late Period, Negative Tests & Symptoms - Seeking Advice

Question
My last regular period was on June 24. My husband and I had unprotected sex on July 8 and 9. I never got a period in July. I took four at-home pregnancy tests (all first response). All of them were negative. The last one I took was last week (8-4-06).
I have had upset stomach, headaches, weird food cravings, frequent urination, a very strong sense of smell at times, basically... many symptoms of pregnancy.
But today (8-9-06) I woke up with what seems like a period. The bleeding is heavy (which is how my normal period is). I also have some cramping but not as bad as my normal period. I dont think this period will last very long because it started out so heavy.
My sister-in-law had her period normally for the first six months of her pregnancy. She did not know that she was pregnant until, after three months, she went to a doctor because she was having symptoms of pregnancy. She had taken a few at home tests during the first month but all were negative also. So, she had figured she wasnt.. until the symptoms persisted..
Could this be happening to me.?
She said that her doctor said it's more common than people think to have a period during pregnancy...
Could I be pregnant?

Answer
HI Sherri,

the only way you will really know if you are pregnant is to  go to the doctor and have a blood test done. This is called a quantitative beta HcG. It will pick up ANY amount of HcG (the pregnancy hormone Human chorionic gonadotropin) in your blood.

I have heard of bleeding somewhat throughout a pregnancy, and not to doubt your sister in law, but periods just do not happen regularly during pregnancy. Some bleeding is common in the first trimester, but not heavy bleeding with cramping on a regular basis throughout a pregnancy. Even if there was bleeding, as if a period, if a pregnant uterus starts shedding its lining that is seriously harmful... and it would not be regular.

So, I suppose anything is possible, but the only way you will know is if you get a blood test. I dont want to sound overly negative but a period arriving is a sign of no pregnancy.

Good luck, I hope thigns work out for you!
andi