My pregnancy test says negative but after 30 mins it faintly tells me it's positive. What I'm confused!!

Letty
So I recently took a first response pregnancy test, the one with the two lines is positive and one line is negative. When I took it and waited 3 mins it came out with only one line, but you know I just had to double check lol. After 30mins it had a faint second line. Is it my mind trying to look for it or what?