I had my normal menstral cycle about 1 week ago (heavier than normal) and have been feeling a little tired. I took 4 pregnancy tests and they are all positive. Is it possible that I miscarried and the level of HCG is still high enough for the pregnancy tests to pick up or is this a normal occurance for a first pregnancy. I am also on birth control does this make a difference? I have not had anyother signs of early pregnancy. How long does it take for Hcg levels to be undetected by urine pregnancy tests? What does the positive pregnancy test mean. Any advice?