In the presence of an enemy, your options for self preservation become simplified, demanding straight action, almost automatic responses to presenting danger.
In the absence of an immediate attack, all one can do is imagine the enemy’s strategies in all its worse possible forms set against all of one’s own weaknesses in all its possible forms. Our battles are thankfully are not all fought at once. The scope for having imagined fear for a battle yet to be fought is huge. The battle can therefore get lost in the battlefield of the mind before it ever actually occurs in reality due to the enormity of our ‘imagined fear’.
When your mind is conjuring up the most frightful images, always remember it often ends up not being as bad as it looks. You can be the conqueror and not the conquered.