Hey there BeingSober. How are you doing?
Is it that unusual to have a blackout? No - not if you drink to excess and/or are an alcoholic. For people without a drinking problem - yes, it's just not going to happen (or at least not happen more than once in a lifetime; 'normal' people would never let something like that happen a second time even if they were daft enough to drink to oblivion the first time).