why do I freak out?

Okay so I would really like some helpful advice on this, I'm 17 and I've been having sex and it's always with protection. Me and my boyfriend would go for a while. (He doesn't finish inside the condom) then I would take the condom off and fill it up with water to make sure the condom is in tact. And they always are. After that we would always wrap it up with oral and that's when he finishes. I am clearly perfectly fine right? How is it that I still get paranoid even when we are super safe?