couldn't find heartbeat

Ali
So I went to express care this morning for some severe back pain. they looked for the baby's heartbeat on the Doppler and couldn't find it. I know it's like finding a moving needle in a haystack but I don't have a doctors appointment for 2 weeks and it's really freaking  me out. Any other moms go through this? I'm only 14 weeks also. Any positive vibes appreciated.