Worried 🙏🏼😔

I went to the ER today with terrible nausea, bad headaches (going on for over 4 days) and some mild cramping. I am 3 weeks and 6 Days according to the app. They did an ultrasound to check on baby but they were not able to find a baby just a sac (which I thought it was okay at almost 4 weeks) My pregnancy levels are at 7,613, is that normal? I need to recheck those levels in the next 48 hours and the number should double. If not double I might have an ectopic pregnancy they said. I’m worried and scared but I am trusting God and his plan. Any input would be greatly appreciated. ❤️