I don’t know when I ovulated...

So. I never took any ovulation tests. I’ve just been going by my app. I’ve downloaded several and they are all different days of me ovulating. However, on February 27 I had something that looked a lot like implantation. (I will post the picture below) I still am getting negative tests. I’m sure it’s too early but what does everyone think? Could I have ovulated before the app said I did and that actually be implantation? I’ve never had spotting or anything....