dude, probably not anaphylactic shock. where are you guys getting this from? anti-histamines STOP Anaphylactic Shock. when the body is allergic to a foreign body, your bodies OVER response makes to many histamines which cause the signs and symptoms of Anaphylactic shock(or any allergic reaction). you can take Anti-histamines, to stop the histamines, to stop the allergic reaction.

with your low BP and pulse, i would assume you took way way way too many downers. hence your altered mental status and passing out for an unknown amount of time. and what you said "seemed like a couple of seconds" could have been hours with your mental altered state. anyways. i bet if you tried Keto again without every over the counter medication you can buy, you would probably just chill out and go to sleep. but now your so sure that its the keto that you'll probably freak out anyways. the mind is a powerful thing. also sounds like your addicted to sleep aids. call that 1-800# on the back of the box.