10 dpo too early???

so I took a test today because I couldn't wait and read that some people get a faint positive at 10 dpo. so I first took a Wal-Mart equate test and it was negative. then I started to doubt it and figured I'd use my first response just because it might detect better if I am pregnant and still nothin. I try to look for a line. hold it in the light and nothing just a shadow. I assume the shadow is just there because that's where the die is??. anyways is it too early even with a first response?? there supposed to detect 6 days before af. the negative first response just basically gives me no reason to hope for this month since they should have already detected. right?