Diagnosed miscarriage

Patient: My doctor said i am about 6-8 weeks pregnant…went in for blood test, level was 7,500. they did a ultrasound as well as a internal ultrasound. said the sac was deterriating…i have some spotting but no cramping or pain. its been 3 days since my ultrasound. could they have been wrong, or seen something not right on the ultrasound? they didnt say anything about a “empty” sac or heartbeat. please help