Day 3 of missed period....

Amanda

So I've been a day late a couple of times before but never more than a day. Today will be day 3 if I don't start today. We inseminated 3 times on my last ovulation which was around 2, 2 1/2 weeks ago. I have taken 3 pregnancy test in the past week and they all say not pregnant. What in the world could be going on? Any ideas would be great. Thanks