measuring 3 weeks behind, doctor just made me more confused

so i’m supposed to be 9 weeks today. my lmp was Nov. 3rd. i had my first ultrasound on friday (8w6d) and i was told the baby is only measuring at 6 weeks and there’s no heartbeat and she called it a spontaneous miscarriage. i haven’t seen the obgyn i chose yet, just her nurse practitioner (i’m not sure why i haven’t seen an obgyn). i wasn’t shown my ultrasound and walked out of the hospital empty handed. my blood was taken to check my hcg levels and the nurse practitioner called me

saturday morning and told me my levels are elevated and when they recheck them on monday if they start to drop THEN i’m miscarrying. i asked her if that meant the baby stopped growing at 6 weeks and she told me yes. i didn’t have my first appointment until 7w2d my urine was tested and labs were done. i guess i’m confused because if the baby stopped growing at 6 weeks why is my hcg level still climbing? why haven’t i had any bleeding or spotting or cramping? i still have sore boobs and i’m throwing up. why was i told i miscarried and then told i might not be? could i have ovulated late and only be 6 weeks along? anyone with a similar experience pls let me know how yours turned out!