Scared and feeling depressed

Nadine
So yesterday I went to ultrasound and there was no baby no fetal pole no yolk sac in the gestational sac went to my obg this morning and he said to expect to lose the baby in 3-4weeks if I don't pass the baby then that I'd have to get a d&c my hcg levels day before ultrasound was 66,651 which was great they are doubling like they are supposed to. Just nothing in sac IDK what to feel or what to do I'm not bleeding I'm still tired nause etc. I should be 8weeks someone please tell me something.......