Stress and Pregnancy

I just went in for an ultrasound this morning. I thought I was somewhere in the 7th week (my last period was June 3rd). Today, I saw the sac which measured at 5 weeks, 6 days. There was no baby found in the sac yet. My periods are very regular so I'm kind of freaking out that I'm only measuring at almost 6 weeks. My brother committed suicide in the beginning of June and the media falsely reported major details about his death. My husband and I are also in the process of buying our 1st home and I'm starting a doctorate program this August.

Is it possible the stress from all of these major events delayed my ovulation thus pushing back how far along I am? Is it normal to not see the baby on a vag. ultrasound at almost 6 weeks? I'm 24 years old and this is my first pregnancy. I have had major breast tenderness for weeks, some mild nausea, exhaustion, and mild to moderate cramps that come and go (not one-sided and confirmed today that sac was in uterus). I am already so in love with this unexpected blessing. I just keep praying everything is normal and the baby is growing! I have no idea what is "normal". Any insights or shared experience would be appreciated!