One time, I was driving at night in the Sierra after a storm - roads were covered in snow. It's a drive I've made close to 100 times without incident. Going around a bend, I saw a car in the ditch on the outside of the curve. I stopped the car, put on the hazards, and went to see if there was anyone in the car. As I was about to cross the highway a car come sliding around the bend more or less sideways. I stopped and…
What kills people is current, not voltage. With AC having your heart beat 50 times a second can also cause you to die hours or even days after receiving a shock, but even that requires enough current to flow and cross your skin resistance. Go to ghe hospital even if you are alive and feel well after an electrical shock! Your heart may have suffered from this.
That being said, there can be many things at play here. E.g. there could have been contact resistance between the live wire and the fixture, which would mean the current that could have flown through your body was limited by that resistance. The reason why you can touch an insulated wire is because there are megaohms of resistance between your hand and the wire. Lower that resistance gradually and there will be a point where you feel the electricity slightly, lower ot more and there is the shock. The most hurtful thing would piercing a wire through the skin, because then the skin resistance is gone.
Aside from contact resistance it could also be that the bath the current took through your body was good (so more on the surface, not across the heart, but down one side of the body and so on).
That being said, your description of the shock does not sound like a fully fledged 230V 50Hz shock to me (certified electical engineer). In my experience you will definitely notice it right away, e.g. because you suddenly just see black and a sharp pain including with extreme vibrations that feel like pure energy is hitting you with a brick in the face. Feeling the vibration like you described it and then making the decision to let go sounds like only a very small current was flowing.