Okay......let's take a deep breath here and examine the issue in detail for just a moment.
OP, the fact that you are in nursing school proves (to me anyway) that you had enough smarts to get yourself there. Thus, if I were your professor, I'd have to presume that you are capable of anticipating the possible consequences of bringing an unauthorized person to a clinical site, and I wouldn't think to tell you specifically not
to do so.
The problem here is that having actually done so, you---rightly or wrongly---will be seen as lacking the prudence and the common sense that is so crucial in this line of work. "Freaking out" and claiming that you didn't know the rules won't fly with your program directors, let alone any professional review board you may have to face. Your best bet is NOT to make excuses, but to admit to using poor judgment and vow to learn from it. This is known in some circles as "doing the ol' humble bit";
IOW, be sorry you did it and don't ever, ever do it (or anything even remotely like it) again.
And for goodness sake, ASK if you aren't sure about whether something is proper or not. I hope that you're allowed to learn this lesson cheaply, but please understand that both your nursing program and your clinical site have an obligation to the patients they serve, and that even potential
violations of privacy are generally dealt with swiftly and severely.