Advice

So I've been tracking my period on this app since June and it hasn't been accurate at all. My last period I started aug 30th - sept 2 Nd . I had unprotected sex on sept 9th. According to this app my fertile window is sept 13-19. I've been feeling a little strange : really sensitive breast I can't even stand my bra , they feel fuller. I have really bad lower abdominal pain on my left side . Can it be a sign that I'm ovulating ?