any advice? negative pregnancy tests

I am 3 days late now for my period, i have take 4 pregnancy tests, a couple before my period was due and a couple afterwards.  They all came out negative.  This is the first month we actually tried for a baby, and my periods are always 28 days apart, and rarely ever late.  I dont really have any symptoms except maybe a little more tired then usual, and my breasts are sore on and off but not too bad.  I am getting a little cramping every now and then but not like period cramps.  Is it possible to be pregnant and just the tests are not accurate?

[New Mommy 2 Be 2007]

well its unusual maybe your period will kick in and maybe not u can go have blood work done to see. maybe u ovulated later and you're pregnant