Dark Positive 2.5 weeks after period. Chemical pregnancy?

The date of my last period was Oct 19, before that it was Sept 21. I got a very positive test on Nov 5. This picture is literally right after I dipped. After waiting 3-5 minutes, the test line was a little darker than the control. I was so shocked because I had just had a period. I took a test because after my period ended, I had brown spotting 5 days later. I called my dr and they think it could be a false positive or a chemical pregnancy because I was technically in my ovulation window. I was on birth control (progestin only), but missed one last month and one this month. This would be my second pregnancy. Now it seems I am having the same early pregnancy symptoms as my first at about 5-6 weeks. Could this be a chemical pregnancy or could it be viable?