Caught Myself Fantasizing About a Patient

I'm a nurse in my early thirties. I've been with Mike for six years now, we have a great relationship and both love sex. But last week, while I was alone at work after everyone left, I caught myself staring at one of the patients. He's a young guy in his twenties who was recently admitted due to an accident. There's something about him that just draws me in, I know it’s wrong, but my mind keeps drifting there. One night, while on shift, I found myself daydreaming and before I knew it, I closed the door to his room and locked it. My heart racing, I stood there for a moment until reality set in, and I left quickly without doing anything. But since then, every time I see him or even just think about him, my body responds. Should I be worried? Is this something everyone deals with but doesn't talk about? Can someone be okay if they have these kinds of thoughts? It's driving me crazy.