Late 3 days negative pregnancy test

Carrie • Married 05/29/2010❤️Son born 08/10/2011 💙Daughter born 02/26/2018💗

We just had our second child on February 26th of this year. I’ve never been irregular as far as my cycle. I’ve had two periods since our girl was born and as of now I’m 3 days late and all 3 test I’ve taken are negative. Every time I’ve been expecting the test always register pregnancy before I’m late! What could be going on? I feel like I’m a little crampy and like I’m going to start my period but nothing is happening. Should I contact my OBGYN Monday if I still haven’t started my period? I’m confused and don’t want something to be wrong. Here’s the photo of the test I just took first thing this morning.