First off, God in terms doesn't send anyone to hell, people do by how they live their lives. Where is your heart?
Now this subject is one not up for heavy debate. God will judge each person rightly, and there is no injustice from his judgement. I see your not Christian, but to realize the Creator, is to realize the depths of His existence. Being suicidal actually takes a lot of false courage to do. When you are in despair, this is a given spot in time to come to God. Not think of yourself. But because man is man, and we cannot alter humanity with human philosophy, we must leave such a thing to God.
To some it's murder, this is true. Since murder is sin, this can be compared to pornography. Just because you feel alone and bored and unloved, doesn't give you the right to view inappropriate material. Just because you are blinded by hate doesn't give you the right to kill someone. Just because your afraid to hurt someone's feelings, doesn't give you the right to lie to people. Just because you have no food and no money doesn't give you the right to rob someone. Just because your spouse isn't intimate with you, doesn't give you the right to cheat. The list goes on...
But I still would leave this topic to the Lord. So don't misjudge the Lord by what many of us Christian's don't know. quite a few of people in the OT committed suicide out of guilt and they were evil in their heart. The Lord judges the heart.
Again people who go to hell, sent themselves there because they didn't want to listen to the truth. Man sends himself to hell, whereas man can also come to Jesus and escape hell as well. Judgement is according to our deeds and/or heart.
But my God is mighty to save, even those who are suicidal.