Ok not sure if this is the same as what youve described but I have passed out after a heavy puff that I coughed my azz off and while coughing blacked out. Now im a Large guy and eat well and take vitamins and such, so I dont think it from a lack of anything. And its happened with different sources and strains so i dont think its laced or anything.
The thing that stinks is is the breakage. See Im sitting at my desk or sitting on my bed. Take a toke, cough my azz off and next thing I know im on the floor and from seeing how i ended up I could only conclude I lost conciousness and slid off the chair or the bed and sometimes my glass ware survives and somtimes we got breakage