Late period but negative pregnancy test

Kathy
Hey y'all. So I am 8 days late but I have taken 3 tests and all were negative. I thought my urine was diluted because I drink a ton of water, but I tested this morning when I new my urine would be more concentrated and it was still negative. I have been tired lately, but no other symptoms really.  I have never been late for my period accept for when I was pregnant, but when I was pregnant before I took a test 3 days after my missed period and it was positive. Has anyone else ever had this happen? Any thoughts/ideas?