Frustrating and worried!

Damaris
Took a HPT (well a couple lol) on 12/7 and they came back positive, went to the doctor 12/8 and got my hcg levels checked they were at 120 went back friday 12/11 they were at 467 and sunday 854. Went to get an ultrasound today but no baby yet. They also send me for more bloodwork. Has this happened to anyone ?