Advice/ could I be pregnant?

Hi so basically wondering if I could still be pregnant? My period has never been more than 1 day late and it’s going on the fourth day but I literally went to the bathroom and there was a little stain of blood. Every period I’ve had obvious and painful cramps but now I just feel like I have an empty stomach. I just stopped taking my birth control pills 2-3 weeks ago (but I only took it for a month)and we’ve been trying to conceive so could I be pregnant? (We’ve taken 2 pregnancy tests and their both negative)