Please help me..

Period is 21 days late, i took a HCG pregnancy test when it was about 6 days late and it came out negative, took another HCG pregnancy test when i was about 9-10 days late and it was negative again, lately i have been getting on and off cramps and it usually signals when my period is coming but it never came, is there still a chance of false negatives or am i being paranoid? please help...

*background*

my period has been consistent with eve for MONTHS and is never more than 3 days late so this cycle has me thrown off