Mommed tests not picking up early positive?

Anyone have experience with this and had this happen. Obviously, it's possible I'm not pregnant but my nipples are on fire which never happens before my period and the only other time it happened was when I was pregnant with my son. I am technically only 9dpo but I was a positive on 9dpo with my first.... and I looked up Amazon and there's TONS of bad reviews saying that those didn't pick up a positive until after a missed period. Just curious if anyone had bad luck with these?