TTC, insight please!


Hey everyone. I just got off nexplanon on November 6, and ovulated a week later, my period was supposed to start yesterday according to this app & I just counted out the general 12-16 days since ovulation to check my period that way & according to that way I am late but every test says I’m not pregnant, I have had a few other symptoms of feeling pregnant. I’m just not sure what to think with tests being negative I know I’m not pregnant but anyone have any insight on getting pregnant after nexplanon ?