How long did you get BFNs before finally getting a BFP??? TTC how long did you get a BFN before finally gettin?

My period is very late (almost a week) but I keep getting BFNs. My cycle is very regular 28 days usually. My question is: how long did you get a BFN before finally getting a BFP or confirmation you WERE ACTUALLY PREGNANT? I have heard that ppl don't get positive tests but ARE pregnant several weeks into the pregnancy, then FINALLY get a positive. I am looking for YOUR experiences.....thanks so much!