Throughout the Bible, suicide is an expression of lack of faith in God to make things right.
Even Job's wife told him that if he lacked faith, he might just as well do away with him self ("Curse God and die," she said, meaning that if he really thought God was being unjust with him, he had no hope to end his troubles but to put himself to death).
However, suicide is sometimes the temptation of people who are clinically depressed for medical reasons, not because of lack of faith in God's love. If you are feeling suicidal, you owe it to God to get a medical evaluation to see if the wish for death is mental, physical or emotional, rather than a spiritual problem.
For a long time, I was in a lot of chronic pain, which made me wish to die to escape the pain. It wasn't a faith problem, it was a medical problem. Once I got adequate treatment for the disease that was causing the pain, the wish to die went away, and so did the depression.