Dark positive?

So I’m suppose to start my period tomorrow but two days ago I got a positive PT. But for being two days before my period is suppose to start, the positive line was really dark! And they just keep getting darker! My last period wasn’t normal. It was odd and mostly dark brown stuff. So I’m wondering if i somehow got pregnant last month and still had an off period thing, or I’ve also been reading that if your positive is super dark, it could indicate twins!😱 how likely is this stuff and what do you ladies think?? I went to the dr today and they confirmed it with a pee test but I should be going back next week for a blood test.