Ladies please I am in need of help.. Yesterday I was so happy but now I feel like I've been hit by a car my heart is breaking and I've been crying for 5mins

Yesterday I went to my doctor appointment and my boyfriend was able to see a fetal pole words couldn't even express how happy I was to hear him tell me even tho the u/s tech isn't allowed to tell us until our doctor sees the images... But I got a call from my doctor and she told me that there was in fact a fetal pole but NO heartbeat and I am currently 7w... I have to go back for yet another u/s with the doctor I really don't wana see, can someone please tell me when a fetus has a heartbeat. This isn't my 1st pregnancy and I hear different things... Please someone help end this confusion