How soon after “implantation” can you get a positive?

I KNOW these can be PMS symptoms. However, never in my 12 years of having a period have I ever had sore boobs and nausea as a period symptom...

I was lightly cramping on the 12th an 13th. I am suppose to start on the 17th but keep getting new progressive symptoms the closer I get to AF. But I tested just now and BFN. 😭

Has anyone tested 3 days before AF gotten a negative and still been pregnant? Or should I just wait until after AF💔😭