Freaking out😭 Need help!!!

Hey guys I just needed a little advice. I always use this app and know it to be incredibly accurate when it comes to predicting when my period is supposed to come on. Even after I take my birth control implant out (which I’ve done twice now) the app still accurately predicts the date of my next period. I’m troubled because my period is almost a whole week late and the app just keeps pushing my period back two days when I select that “I’m late”. I was also cramping extremely badly when my start date was closing in (as usual) but nothing happened. I took a pregnancy test on the 21st of this month (the predicted start date) and the test came out negative. My bf thinks I didn’t pee on the stick long enough but who knows. I’ve just been trying to wait for my period to start. I’m not worried if I’m pregnant. I’m worried if the birth control implant messed up my body!! How much longer should I wait to go to the doctor? It’s about to be November and i haven’t even gotten my period for this month!