Ali , That has to be awful scary ... have you changed any of your meds lately ? I know I had a similar issue sev. yrs ago and it turned out to be one of the antidepresents they had me on . Not sure which one (brain fog) , but when I weaned myself off ,that problem went away . mine came on and felt like a very sudden (within seconds) drowsiness and I would pass out/fall asleep mid sentence of talking with someone or whatever I was doing , and would awake unaware of anything I missed . I usually would have a second or two to react and I would make sure to position myself not to hurt myself . Good luck and take care !