Had sex night before had some pink spotting yesterday went to er hcg levels 170 to 178 they didn’t even see a sac via both ultrasounds spotting stopped completely no pain or cramps is this normal? Plz help I’m freaking out

Update: last night I started spotting red and this morning it was heavier with small clots later this evening I passed two pieces of tissue maybe the sac not sure but after I passed cramps lightened up and now back to spotting I go to the doctor Tuesday

UPDATE 2: levels went up to 630 but still didn’t see anything on the ultrasound and there was no indication of a miscarriage so we still not sure of what’s going on I go back to the doctor for ultrasound on the 18th