Can't trust FRER for testing early

So I took a FRER the day before period supposed to start. Positive! Yay! The line wasnt even faint. Two days later, took a rapid response first response...negative and started bleeding. Then I saw this on the box...

They shouldn't even have this test!! Why give women false hope? Dont test until a day or two after your period. It will save you so much heartache (this is my third chemical). I'd rather have not known.