Is my wrist BP cuff saying irregular heartbeat reliable?

[tdomine]

I am 21 and rarely take my BP because it's always fine and I don't have any health issues and don't take meds. My dad was taking his so I decided to put the cuff on and take my BP on a whim. The irregular heartbeat symbol showed up. I took my BP again a minute later and it didn't show up this time. I have pretty bad health anxiety so I'm thinking I'm dying now and having irrational thoughts. How reliable is this symbol? It's a wrist cuff and is often really hard to get it to even work correctly. Should I tell my doctor? My family members are acting like I'm ridiculous and just shrugging it off.