Spotting 5 days before AF due

Jennifer
Hello lovelies! So I woke up this morning to to some light pinkish-brown spotting. Nothing in my underwear and only when I wiped. It was super sticky. My periods are so regular, my fiancé knows exactly when I'm supposed to start... Which is on 2/29. Could it be implantation bleeding so late? Any thoughts are welcome. Thanks in advance for all your advice.