First ultrasound jitters

I have my first ultrasound today. While I'm very excited, I'm also equally nervous because about a year ago, my mom went in for her ultrasound and they couldn't find the heartbeat. In April, I lost my baby right before my ultrasound. I'm scared that it'll happen again. I hear and read about women who have multiple miscarriages in a row and I'm just so terrified to make even the smallest mistake. Has anyone else felt this way?