In the yoga tradition, it's called *tapas,* or the fire of determination, the fire of transformation. It is the spark that drives us to action, and while fire can be both cleansing and destructive, it must be harnessed or, at least watched.
Either way, it must be used. It can't be saved, tucked away, only to be retrieved when we've nothing better to do.
In that case, just ignite another spark.
But in the meantime? Use the fire you've got and burn, baby, burn.