From what I know about
ATIVAN (Lorazepam) is that it is for anxiety sometimes. It was once prescribed to me and the Doc told me ot was the kind that hits ya quick and fades away. I am pretty sure it also has a very short half-life. so its out of you quicker than most pills.
So I would have to say that your symptoms to not agree with anything I know. it should not last 16 HOURS!!!!! If you did black out from it, it would not be very long. Its, to me, one of the weeker Benzo's. So I am not sure what you popped the other day?