Am i the only one reading my iPhone messages?

Ok this has to do with my phone and messaging because my dad first made the iCloud account and then i found out he was receiving and reading my messages. So i made a new iCloud account just for myself and my own number. But for some strange reason i feel like he's getting my messages. Like whenever i get a message, he will get one too at around the same time ( i know because of his text tone). So how can i tell if i'm the only one receiving my messages or not? I might just be paranoid.

In my settings it says that my number is the only one receiving and sending the messages so i guess i'm fine?

Turn imesasge off and back on, so you have to sign in again, I'm assuming you already did that with your new ID and password.