Patient Confidentiality Violation?

I work as a nurse in a bustling city hospital. The ER gets filled to the brim every evening and into the night with people from all walks of life seeking urgent medical attention, ranging from broken bones to drug overdoses. One particular evening stands out among all others for reasons I would rather not think about too deeply. It was around 10 PM when a young woman in her early twenties arrived at our department after being found unconscious on the street by a passerby. Her heart rate was dangerously low and she had some superficial cuts from falling, but otherwise nothing life-threatening. We ran all the necessary tests and stabilized her condition while waiting for an ambulance to arrive. As I was preparing her medical records, one of my colleagues mentioned in passing that this woman's name was Sarah (she had previously been brought here before), which piqued my interest because one of our staff members, a fellow nurse named Mike who works on the other shift and isn't from around these parts originally, used to date someone called Sarah while living back home. This detail nagged at me until I decided that I needed to confirm if this was indeed her. The next day during my lunch break, after ensuring no one else was around and making sure we had privacy, I approached Mike in the staff lounge with a not-so-subtle question about whether he ever dated someone named Sarah who now lived here. He didn't know anyone like that locally but said his ex-girlfriend back home was also named Sarah. Feeling guilty yet curious, I returned to my computer and pulled up this patient's file again, scanning it closely for any mention of a home address or phone number - anything that could connect the dots between her and Mike. But there wasn't enough information available for me to make that leap confidently without breaching patient confidentiality in the process. I've never felt such intense regret and shame over something I've done professionally before. Even if it's just a hunch, my curiosity has potentially jeopardized the privacy of one of our patients, and this is something we take very seriously here at work. The worry gnawing at me now about how much damage could have been done by simply asking an innocuous question in passing makes me feel like a terrible person. And so I come here to just get it off my chest - no judgment needed, really; only relief in sharing this burden with someone outside the hospital walls. It's not something I'm proud of or that I'd repeat given another chance.