hi..thanks for writing.. i have understood your problems.. committing a suicide in depression suggest severe depression which requires hospitalization and treatment under the observation of psychiatrist.. if you are on antidepressant medications and not improving then consult your treating psychiatrist for change in medication or increasing the dosage..if you havent seen a psychiatrist till date, I would say , you shud visit one... you shud also have to observe your personality problems...if there are any... change in the thinking like pessimism, negative views about oneself, future, world are common in depression ..also it causes helplessness, hopelessness and worthlessness..which is the reason for suicidal ideation... decrease concentration in work may be related to depression which is bothering you right now... in my opinion consult a psychiatrist and ask for help..follow advice..depression can be treated with antidepressant medications and psychotherapy..[particularly by CBT].. i hope this advice will be helpful to you...best luck..