At 17 dpo ultrasound shows nothing !!

Hello all... have been trying to conceive for 2 years...finally tested positive on 14 dpo. Blood work on the same day came up with 195 bhcg. Though my menstrual cycle was on 25th jan I generally have a 35 day cycle. an appointment today for ultrasound which according to doctors makes me 6 weeks pregnant shows nothing. Absolutely nothing. I am scared to death on what is going to happen. Have some more blood work tomorrow to c how the hcg level is progressing.

Any of you girls have faced any similar situation? I have already had a miscarriage in July 2017 in a similar way.