5 weeks no heartbeat?

So I’m super stressed. I recently found out I was pregnant... It was confirmed through the ER that I was pregnant but very early. I set my first appointment for this Monday. Yesterday while at work, I was having cramping, diarrhea and stomach pains (it felt like the stomach bug). I went back to the Er to make sure I didn’t have the flu or anything since my son was just diagnosed with the flu a week prior. They wanted to do a vaginal ultra sound to see the baby. Later on, the nurse come into the room and says act surprised when the tell you but they see the yoke sac & the baby inside everything seems to be growing in the right place. There was no fetal heartbeat. I instantly start freaking out and she’s like calm down you only 5 weeks. You usually don’t hear until 8-9... I’ve been stressed ever since guys... can anyone reassure me this is normal??! With my son I found out I was pregnant at 12 weeks so I do don’t have to go through any of this 😔 sorry for the long post!!!