Help Please

So last period was July 28-2. We have been trying. (including August 17 we tried) Took my first test August 27 and it was a faint positive another one a couple days later and also positive. Sept 1 I went for blood testing. Sept 4 I hadn't heard from my doctor but took another test and it was also positive. Went to my doctor this past Thursday cause I had not heard from her yet and it was negative along with a negative at home pregnancy test I didn't ask my levels. I have an ultrasound booked for tomorrow. Just confused as to what is happening. I haven't had any bleeding and still have all signs of pregnancy  can someone help with opinions? Ive also never been late on my period before.