Positive preg test only on one brand?

Hi guys

So I had a positive pregnancy test and continue to get them with the tests we use at work. They measure (25iu) then when I test on other brands I don’t really see a line? Went to the doctor on Thursday for a blood test but results won’t be available till Monday 😰😰😰🆘🆘🆘. Showed my

doctor the picture of the tests and he said yes you’re definitely pregnant but why am I not showing up on first response or any other brand? Anyone had the same experience?? See attached picture (they al look like this and come up within 1minute!!