> Whats the normal stockpile?

For jet fuel? The article does not say, but if they are correct in predicting shortages in six weeks, then the stockpile (if any) is not terribly large.

> Isn't the entire US national strategic oil reserve only enough for like 1 month of US usage?

In any case, whatever it is, crude oil is not yet jet fuel. The crude has to be refined to output jet fuel (and other oil byproducts), and some amount of gulf refinery capacity is also offline due to one or both of damage or inability to export via sea through the strait.