First ultrasound today!

I have my first ultrasound today. I am nervous. I had two miscarriages before I had my son who is 17 months now. Both of my miscarriages were early on when I was 4-5 weeks along. I have not had many symptoms with this pregnancy besides exhaustion and tender breasts. My stomach feels weird at times but not really nauseous. I am just worried that we will go in and there won't be a heart beat today with my lack of symptoms. I had horrible morning sickness with my first. I ended up not being able to work because of it. This pregnancy is completely different already!