Is it possible that Pregnancy Test Home Kits fail to detect pregnancy?!

Is it possible that Pregnancy Test Home Kits fail to detect pregnancy?

I missed my period for 2 months now. I had tried pregnancy test kits for 2 times now (last was this morning), but they always turn to negative. I have from time to time pain in the nipples, and in my lower back. Is it possible that I'm pregnant although these pregnancy test kits always turn to negative?

I need an answer..

Please I don't need an answer like :"GO TO A DOCTOR/OB-GYNE"
I already know that. I just want to know others' opinions about this.

hm,have you followed the directions on the little pamphlets that come with them and using them in the morning..
the day of or day before your period?yes it is possible that they are coming out wrong....
are you having other symptoms?weight gain,hard tummy certain smells make you want to gag....strange cravings? nausea...frequent urinating?im not going to say 'go see the ob/gyn' because you dont want people to....but.....if i were you......