I came across your post, and wanted to let you know I am in the same boat. I also miscarried on Feb 26th and am having the EXACT same problems. My tests have been negative as well, so I guess only time will tell. (Which is a ridiculous thing for me to say because I''m super impatient.) Have you noticed any swelling in your lower abdomen? Ovarian cysts can sometimes have the same symptoms of pregnancy. I have a history of ovarian cysts, so that could be a possible explanation, if not pregnancy, for this mystery. Anyway, no answers for you, just wanted to let you know you''re not alone. Good luck to you, I hope you are indeed pregnant!