Has anyone else had this?

Had my first ultrasound on Thursday and it only showed a gestational sac at 6w. My HCG level that day was 1622. Had my blood redrawn Sunday and MY HCG had only increased to 1915. I talked with the nurse who didn’t seem to hopeful. Told me to watch for bleeding and cramping. I’ve had no symptoms like that. I have had breast tenderness, nausea and food aversions that haven’t gone away. The nurse at my clinic said there’s nothing to do but wait for my next ultrasound to see if there’s a heartbeat. Has anyone had a similar experience and what was the ultimate outcome?