First response early result

How do yall feel about first response early result tests? I just took one two days before eve expects my period (I’m not always consistent so it is still a guess) but I’m still getting a negative result. Has anyone else had them not work but when you take another one on the first day of your expected period it’s positive? Just wondering how often they’re wrong. It could just be that I ovulated at a different time but I was really hoping eve had predicted correctly.