so sad right now

went to my second ultrasound today and found out that they couldn't find baby a's heartbeat i am seven weeks and five days with twins ..i think i need a second opinion bc the lady didnt seem really positive on what she was doing and it was at a pregnancy center bc i cant get into the ob yet bc my insurance hasn't been switched yet im so sad confused bc just monday when i went to the er they were fine both had amazing heartbeats ...anyone ever have this happen and the baby turned out okay ?