As one who must deal regularly with fear, I found this piece by Father Bede Jarrett to be so helpful, and I hope you do, too.

Fear is a weakness and a strength, a sin and a virtue.  For most, it is probably an evil, since human nature shrinks from present pain and is the more vividly afraid of what more immediately threatens.  For that reason, it would appear that man is more likely to be too much, than too little, afraid in life.  No doubt there are many who need to be more circumspect, more cautious; but these adventurous spirits are fewer in comparison than those who find in the life of the soul too much matter for depression and discouragement.

Naturally the real determinant a to whether fear is legitimate is to be sought in ascertaining the object of fear: Obviously the whole question is: “What exactly is it of which I am afraid?” . . .

What signs can I look for to discriminate between the right and wrong fear?  This surely is the infallible test: the fear that is really and truly from God should take me nearer and nearer to his feet; a fear that keeps me from his presence and holds me at arm’s length from him can never be his gift . . .

So, then, the true fear of God should hold me to his love and his reverence.  It must prevent me from turning away from the pathway of his commandments, nor should it further disturb the peace and serenity of my soul, nor torture my conscience nor bruise the tenderness of love or lead the enemies of God to speak of him reproachfully.  I may know what is a false fear of God, for it will lead me from him.