I have struggled in this arena as well. I tend to be my own worst critic or enemy. The negative thoughts I indulged in have contributed, for the most part, to my major depressive episodes. This has been largely due to the fear of sharing those thoughts with others because I didn't want anyone else to think of me as horribly as I thought of myself. Feelings of guilt and worthlessness can easily overtake you of you are not careful.
The best thing is to get the thoughts out of your head. Write them down, share them with someone you trust and believe loves you, or record them on a tape recorder to playback. I think it helps just to keep them from bouncing around in your head. Once they are out you can get a different perspective on them. Viewing them on the outside helps to explore varying angles of those thoughts. You are in a better position to examine and filter through them for deletion or maintaining.
Perhaps therapy or some form of counseling will help you sort through these thoughts. We can get so caught up in this that it brings on an illness that requires treatment with medication to adjust or balance certain levels of secretions in our brain.
There are times when we need to do a self analysis. We need to be cognizant of those areas or issues in our lives that need improvement or adjustment. We are not perfect nor can we ever be. We can only work to do and be better first to ourselves and then for others. Mistakes and failures in life can be frightening and stagnate us because we are unable to see a way beyond/around that speed bump in our road. Or they can be learning lessons for the future.
"Serenity now, serenity now!!!!!!!!"
God grant me the serenity to accept the things I cannot change...The courage to change the things I can... And the wisdom to know the difference.
It may help to make a list of the positive things you know about yourself and that others have brought to your attention. Use these and what God says positively about you as weapons against those negative thoughts. Put them up somewhere you will see them daily as a reminder; on your mirror or wall.
Redirect those thoughts towards doing positive things. Walk or exercise listening to music you enjoy. Christian and Gospel music are uplifting and encouraging for me. I also enjoy R&B, jazz, hip-hop, and classical music. Learn something new by reading a book or taking a course. Treat yourself to a day spa for a massage or a facial. Visit family and friends. Do volunteer work in a school, hospital, retirement home, etc. Go bowlling, go to a movie, go to a concert or play. Find things you like to do and do it.
A guideline for a healthy thought realm lies in scripture:
Phillipians 4:8 "Finally, brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good report; if there be any virtue, and if there be any praise, think on these things."
II Corinthians 10:3-5 3) "For though we walk in the flesh, we do not war after the flesh: 4) For the weapons of our warfare are not carnal, but mighty through God to the pulling down of strongholds; 5) Casting down imaginations, and every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ; 6) And having in a readiness to revenge all disobedience, when your obedience is fulfilled."
Ephesians 6:10-18 10) "Finally, my brethren, be strong in the Lord, and in the power of his might. 11) Put on the whole armour of God, that ye may be able to stand against the wiles of the devil. 12) For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places. 13) Wherefore take unto you the whole armour of God, that ye may be able to withstand in the evil day, and having done all, to stand.14) Stand therefore, having your loins girt aboout with truth, and having on the breastplate of righteousness; 15) And your feet shod with the preparation of the gospel of peace; 16) Above all, taking the shield of faith, wherewith ye shall be able to quench all the fiery darts of the wicked. 17) And take the helmet of salvation, and the sword of the Spirit, which is the word of God: 18) Praying always with all prayer and supplication in the Spirit, and watching thereunto with all perseverance and supplication for all saints;