Missing period...one positive, four negative....12 days late

So I recently had to stop my birth control for a little over a month because I am waiting to start a new birth control. Well my last period ran from August 5-August 20. As of today Sunday September 13 I am 12 days late! I took a dollar store test Tuesday it came back positive. Took a test later that day from First response negative. Got tested at the doctor negative. Tested Friday and twice today negative. Still no period but I'm guessing my dollar store test was a false positive and a dud test. My doctor said to retest again on this coming Sunday at 10 days of negative come in for blood test. Tuesday will put me at 14 days late. There's no way I'm pregnant! A test by now would be positive. Both previous pregnancies showed up no later than 6 weeks. No symptoms just bloating, frequent urination, and sore breasts. I am going crazy taking tests but they all say negative except for the test I took last week. What is going on with me?