uhm help . . like asap . VERY LONG

so I went to the OB on the 22nd pregnancy test came back negative told me I probably got faulty tests . . and that my PCOS was probably getting worse ?? and that when my period starts back up again I WONT know it'll just be HORRIBLE & like niagra falls in a nutshell . . I won't spot it'll just begin . . well went to the bathroom & I'm like half asleep I wipe and there's light pink / light light red more like a pinkish color to me because it looked no where like AF . . sooooo let's say it's implantation bleeding how long after that occurs can you test ????? . .

and I don't have period cramping but slight not like a period at all . . . NEED HELP AND ADVICE .