How far along ??

I just got a positive test,, but idk how many weeks I am I have 25 day heavy heavy cycles (about 2 packs of tampons per cycle) and they last 7 days, but my last period was on March 12 and only 4 days. And I only needed some period underwear and pads. Maybe it wasnt a real period and I'm farther along? I'm so confused.