lost my cat

Refers to those times when, having imbibed too much, (maybe you inhaled too much, or drank way too much, or ate too much sugar…) suddenly you find yourself entirely unable to function properly and you end up doing something REALLY stupid, dangerous or even life threatening. "Too much, too much, you took too much!" Dr. Gonzo, Fear and Loathing.
(Don't remember anything that happened? Don't worry; your friends are always keen to tell you all the details the next day.)
Note: Also can be referred to as an AFE - "alcohol fueled event"