Can prometrium promote a positive HPT?

Here's the deal- please don't think I'm crazy, but I have now taken 24 pregnancy tests, keeping count I have had 14 definately positives (not in a row), 8 I think I see it there, and the rest have been definately NEGATIVE. I went to the doctor after the finally 1st positive just to have a negative urine test at the office, she did a pelvic exam and said that my uterus was significantly enlarged, but didn't think that I was pregnant. I've had 2 blood HCG's and both have been negative.. I feel pregnant and this is my 3rd pregnancy. My last one ended at 15 weeks due to chromosomal abnormalities, but I have a beautiful and healthy 3 year old little girl at home. Even with negative blood tests I have not been convinced that I'm not pregnant and I've had positives still also with HPT's. Dr. put me on Prometrium and in the 1st week the tests were negative, but today (my last day of prometrium- I've had 2 very positives) My last MP was June 17th and was 4 days late and only last a day and 1/2. I had some brown spotting over the last week, but would barely even classify it as spotting. I'm feeling so lost and confused and I'm afraid to call my doctor and insist that I'm pregnant, since pregnancy is not exactly a mental status. Maybe it is on some level, but I don't think that I would have DEFINATELY Positive HPT's if this were the case. Any recommendations would be helpful. Any similar stories would be comforting.