Can’t find heartbeat with fetal doppler

Yesterday at my doctors I went in for my appointment and I am about 9weeks 5 day and she wanted to used he doppler on me but said she couldn’t find it and set up and ultrasound for me :( it only makes me upset because my cousin who is 4 days behind me has the same doctor and was able to find hers. Has anyone one had this happen then on the ultrasound be just fine? I get worried about this easily plus I am having problem getting me appointment set up which doesn’t make things easier. I know there is a possible chance but I feel fine