First Trimester Measurement Craziness

Laura
Hey ladies. I'm probably just shell shocked from my miscarriage in Novemeber but it is what it is. Sooo, I had two ultrasounds very close to each other (my boobs stopped hurting and my ultrasound tech was super understanding). At 6+6, it measured 6+6, but then at 7+4, it only measured 7+3. Is it a bad sign that it only grew 4-days-worth over the course of 5-days? Or is this totally normal and am I being super nervous for nothing? 
Thanks!