I should also have said that stomach pain can be caused by many things which is why it is best to check with you GP who can advise you better. It is worth noting though that in early pregnancy when the embryo is attaching itself to the womb , abdominal pain can be felt and in some cases , there may even be slight blood loss. It is only usually a worry if the pain is severe , concentrated down one side of the body or and/or accompanied by heavy blood loss. I tested negative on two occasions with my youngest daughter before testing a third time to find it was positive. My doctor told me that I was probably testing too early and that the test did not detect high enough levels of HCG to produce a positive result. Don't worry though , as I said it could be something and nothing. Speak to your GP x