How long did it take to get a positive?

I'm 3 days late, and I know that's not super late, but I took a test this morning and it was negative. I'll test again in a few days if af doesn't show but when can I expect a positive if I am actually pregnant? I'm normally very regular but back in September my period was a whole week late for no apparent reason and it's driving me crazy that it's happening again. I don't want to get all worked up just to get my period like last time but I also can't think of another reason my period would be so late again. Back in September I attributed it to my stopping birth control about six months earlier. Like maybe it was just regulating? But now idk.