4 days late

I am four days late, my periods are always on schedule. I only been late once but only for two days but that hasn’t happen for 2 years now. I took a test yesterday but it was negative it wasn’t my first pee not sure if that make a difference. Did I test to early? Or is it really a negative! We have been trying for 2 1/2 years. I been having some creamy discharge for the past two weeks as well