Yes I would go back to the Dr and have a BHCG done to see exactly what the levels are. If they are very low and thats why the preg tests are coming up negative I would be wanting further investigation like is it rising, falling etc and if the BHCG is above 5. And if its not I would be wanting to see why you haven't started bleeding. Sounds like there definately was or is a pregnancy there which has given you the positive tests but I would be wanting to know if its still progressing and if not why. Was it a chemical pregnancy or something else. I am sorry to hear the wait has being difficult for you and not straight forward like ti should be. I have had a similar thing happen to me in the past and felt like I was pushed from pillar to post. Like no one wants to find answers for you or wants to help when clearly you know things are not right. Hoping you get some answers soon.