Nurse Fantasy Gone Too Far

I’m a nurse in my 30s with a rather unusual fantasy: I’ve always been fascinated by the sterile environment of hospitals and the power dynamic between patient and caregiver. Last week, I tried acting out this fantasy with my girlfriend, who’s incredibly supportive but not into roleplay. We agreed it would be consensual, but when she laid on the bed pretending to be sick, something snapped inside me. I started treating her like a patient, getting too intense with the care and authority. It felt exhilarating but scary, was this just a harmless fantasy or something deeper? What should I do if it happens again?