5 weeks 3 day pregnant only sac

Tatcha • 1st IVF/ICSI FET 12.13.18 🌈👶🏻 EDD 08.31.2019 Sebastian was born 9.4.19 9lbs 8oz

I had to go to ER today because my left side waist keep having pain so I thought I might have an ectopic pregnancy. Luckily the ultrasound showed I don’t have. They only found am empty gestation sac. No baby or yolksac. Is it normal at 5 weeks 3 days? Now I’m so worried. I hope I don’t have a to end up having a miscarriage because this will be a second time :( my HCG level is 3782.