Yesterday, 3/18/17, I got a positive test. My last period was 2/3 and lately they have been 28 day cycles. Well I missed my period on 3/4, so about 2 weeks ago (the 5-11) I tested every couple days, all negative. Decided to give it a break the following week. Well Saturday I ate and got nauseated and decided to test one more time. Bam! BFP. Are my weeks off? Because according to the app I'm about 6 weeks, Due on Nov 11.. Has anyone had this happen?

Thanks!