Do you have negative thoughts that bother you? I am realizing there are patterns to mine and some cause me to plunge into various areas of depression if left unchecked. If you are willing to objectively listen to your negative thoughts, you can pick out patterns after a while. Then you have choices to make. We have a responsibility to do our part in fighting against this darkness.
Perhaps your thoughts concern your job. The various things you do not like about the job. Not necessarily enough to make you quit or seek another position, but misery builds. Regardless of the financial security and health coverage you may be given, those thoughts can pull you under into a mud puddle until you are bathed in loathing about the work you need to do.

Maybe someone in a group of your peers trigger negative thoughts. All humans have weaknesses and failings. Perhaps you let some behaviors bother you. Soon their aggravations are like burrs under your saddle. You get more and more unhappy, knowing they are not likely to change and blaming only them for the problems between you.
Feelings of inferiority or fears about being less than others can color your outlook on seemingly innocent exchanges. Soon you can interpret everything and everyone as shunning you.

What are your patterns? Have you taken them to the Lord for help? The Holy Spirit can guide and direct us if we are willing to be instructed and led in paths of light. We have a responsibility to do our part in fighting against this darkness. We are responsible for the thoughts we entertain. What is your process when you recognize a pattern as familiar, something you have experienced before?
Indeed, we live as human beings, but we do not wage war according to human standards; for the weapons of our warfare are not merely human, but they have divine power to destroy strongholds. We destroy arguments and every proud obstacle raised up against the knowledge of God, and we take every thought captive to obey Christ.
2 Corinthians 10:3-5 (NRSV)
Are you doing your part in this warfare? Do you push back against the darkness or just take it all as if you believe you deserve it? Are you willing to take every thought captive to Christ?
Years ago we were taught with a saying that became somewhat common, “Feed your faith; starve your fears.”
The LORD is my light and my salvation— whom shall I fear? The LORD is the stronghold of my life— of whom shall I be afraid?
Psalm 27:1 (NIV 2011)
This song might help feed your faith and starve your fears. Watch your thought life. It might be your best defense against the negativity that would like to pull you down, and under, drowning you in defeat. Cling to the One Who loves you most! The biggest battlefield is most often between our ears!