Wtf happened!? (choking) help!

My bf normally chokes me as that is our kink but he just did it and when he let go my body involuntary started shaking, it was almost like a seizure. My hands went crazy, my body lost control and I couldn't control what was happening. Once it was over I'm honestly freaked right the fuck out, wtf just happened. It scared the shit out of me, I couldn't stop what was happening to my body until it passed. 😭 this has never happened before, I started twitching excessively and I couldnt stop it. I'm now shaking.