23 days late?

My Fiancé and I have been trying for baby number 3 since October and as off today I am 23 days late. I have taken four pregnancy tests, one a week and they have all come back negative. I have been sick a few times but I work in healthcare and the GI bug has been going around all winter, so it could have been that. With my last two pregnancies I knew early on the that I was pregnant, felt the symptoms before even taking a test and before I had even realized I had missed a period.