Could the tests have been wrong?

The first day of my last period was Nov. 13th! I took a test one week after I had not gotten my period in December. It was NEGATIVE. I took a test one week later, since my period has still not came, and it was NEGATIVE. Though I’m seriously beginning to wonder if they are wrong. I still have not had my period, i’m hungry and my lower stomach below the belly looks wierd, it’s a little larger and and is hard. I have a friend who’s working with a pregnant lady and studying the midwife thing, she felt my stomach and thinks that there definetly is a something growing, she thinks i’m somewhere from 1 1/2 months to 2 months, but I told her I tested and they were both NEGATIVE. The latest thing that has happened in the last two days is that my breasts are hurting, tender to the touch, now I’m seriously beginning to wonder if they were wrong, or to early to tell. I’m just confused!!