Emotional roller coaster

So I went to the dr on the 17 thinking I was 7 weeks. Dr only found an empty sac. Went to the we in Wednesday for cramping and they found a baby measuring 6weeks 4days hb 115. Went back to my obgyn for another ultrasound and baby was still only measuring 6w 4d but heartbeat was 145. Went back today and baby was measuring 7w 4d but they were not able to find a heartbeat. She wants me to come back Friday for another ultrasound and go from there. Please someone give me some hope. Or should I plan on being out?