Hi,
The way I see this problem, its not something that u created and thus not capable of resolving because it's an illness with exact symptoms that you described... This is Depression and just like any other illness u have seen in life this requires treatment. Believe it or not but the things u mention seem so much personal and Individualistic but the reason why u get such thoughts and why u can't get such negativity provoking thoughts out of your mind is due to biological deficiency.... Which if corrected will relieve you from the problems.
Next Steps
Usually milder intensity problem is treatable with counselling or psychotherapy but in your case the intensity and impairment is severe enough to call for medicines along with psychotherapy (talking /discussing /counselling).
So please enable your freedom from this illness by either seeking help from any psychiatrist of your choice.
Health Tips
Feel free to raise any further concerns...