Irrational fear???

I love/hate going to get ultrasounds because I'm terrified of not seeing a heart beat and something happening to my baby!! Is this an irrational fear?? I'm a FTM and I'm constantly worried and always ask my partner for reassurance that the baby is indeed still in there. I was going to look up what are the odds of losing my baby but decided not to. No one in my family has ever lost a baby except my cousin but that's due to her ovarian cancer. Does anyone else get this worried and anxious about ultrasounds?