Help calm my nerves 🥺

I am currently 13 +1 weeks. I am so scared of going to an ultrasound or just a regular appointment and the doctor not being able to find my baby’s heart beat. What brought these fears on were some horrible nightmares I had a few days ago about this randomly happening to me. Please someone tell me that the odds of this happening are low 😭😭😭 I am so terrified of this that it’s making me not even want to attend my appointments (which I obviously will still be attending). I feel as though I’m just going down an anxiety rabbit hole for no reason as I haven’t had any complications with this pregnancy so far.