sadch,
People will have different answers based on their beliefs. People who are heavy into eternal security are going to say suicide won't send a Christian to Hell. People who believe if you die with an unconfessed sin you go to Hell.... self-murder as the last thing you do? Wow. They are going to think a different way. And the idea of being depressed, killing oneself, and then being depressed AND burning in incomparable painful fire for all eternity on top of feeling depressed is an awful thought. Be that as it may, you will have to stand before God and give an account. I believe believers who end life 'okay' in regard to their eternal destiny are still going to have to stand before God and give an account of how faithful they were with their lives.
God gave you your life, and it would be extremely foolish to throw you away. Do you remember the man in the parable who was given one talent? Even if you don't think much of your life, you don't want to fail to make good use of it like that man in the parable.
I do not know what happened to you. But do not make a permanent decision based on a temporary problem. If your issue is just the pain you feel about something is immense, that's terrible, but emotional pain does go away. It does lessen over time, and it is possible to be healed, emotionally by God.
Let me also share a little experience of mine. I had a close female friend once. We weren't dating, but we were close and there were a lot of emotions. One day she told me on the phone she didn't want to be a close friend of mine anymore, and she also said some other things that hurt me. That hurt, but the next morning was Saturday or a holiday, so I lay on my bed thinking all these thoughts about how bad she was and how bad what she did was. It was like it was addictive to think these thoughts, but as I thought them, it was like a knife jabbing into my heart.
Someone at church had a vision of an enemy shooting arrows into my heart and me allowing it. This was from the group that prayed before church. So they prayed for me, including the person who'd hurt my feelings, and I was about 90 or 95% better after that.
What I learned from this is what it can be like if accept thoughts demons put into your mind. I didn't know that was what was going on at the time. I remember another time when I was young, and something had happened I didn't like, but it wasn't nearly as painful as this. On a long road trip, the idea of just killing myself with the car at a high speed came through my mind. I realized, though, that that was stupid, and I might have realized it was demonic.
I wouldn't be surprised at all if some of what you are experiencing is demonic in nature, demons putting thoughts into your minds, and instead of rejecting the thoughts, you accept them. II Corinthians 10 talks about bringing every thought captive to the obedience of Christ. Christ did not teach you to commit suicide. Memorize some scripture. Maybe that verse about 'rejoicing in our suffering' might help you. Psalm 42 tells about David feeling downcast. He talked to his soul and said he would hope in God and praise Him. That's a solution for you. Talk to your soul (talk to yourself) if you have to. Quote scripture to yourself. Say, "I am not going to think those thoughts. My life is valuable. I am fearfully and wonderfully made. I must use my life to glorify God" and pray to the Lord for help. Do like David. When you are downcast, praise the Lord. Do what James says. If any is afflicted, let him pray.
Don't lose this battle. Just imagine a small gang of demons around you. One of them throws a thought your way, and if you accept it they all join in and start laughing and mocking as they give you more suicidal thoughts. But now imagine that thought crosses your mind, and you say 'no' and you quote scripture with resolve. You start to pray. Now imagine they get scared and run away. Why would you want to lose a battle like that?
As far as emotional pain goes, you can be cured of that. Spend time in prayer and the word and meet with other believers who can pray with you about it or just talk with you. That kind of pain doesn't last forever, and the Lord is very able to heal you. I was healed from horrific emotional pain in an instant when people prayed with me about it. Don't give up hope.
Also, don't focus on how you feel and how the decisions you make will effect how you feel. Rats in a maze do that. If the food tastes good, they'll push a lever or jump through hoops. If there is an electric shock, they go the other way. Instead of making decisions based on how you feel, make decisions on what pleases the Lord. You will likely feel much, much better soon if you do that and seek Him. Use this pain as an opportunity to draw closer to God. There is more to you as a person than just how you feel at the moment. You are bigger than that.