Do not commit suicide, everyone sins and you need to realize that even Christians do. However, that is not an excuse to continue sinning. You need to get victory over the spirit of lust operating in your life. Pornography is a cancer to the soul, and you will only weed it out by seeking God's help through prayer, reading the word, and casting all vain thoughts/imaginations down. I had a hs friend who struggled with this and I told him some tips to help him.
1. Your mind needs to be renewed. There are several verses in the Bible because all sin no matter what starts with a thought! 2 Corinthians 10:5 5 Casting down imaginations, and every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ;
an excellent verse to bring to mind when you have lustful thoughts or urges....also saying "I burn out these thoughts with the blood of Jesus" is powerful, the blood of Jesus has real power....
2. Put a wooden cross, or verse to remind you of Jesus sacrifice for your sin of pornography...mind you this is not iconism/idol worship...just a good physical reminder to help you remember that every sin Jesus took on the cross, and that when we willfully sin knowing this, I told my friend to picture himself nailing Jesus to the cross when he did that sin....he said it helped him when he put this next to his computer/tv. Also, clean your browser from all the websites, cookies and history of all these sites....use a wallpaper with a verse on it.....just my suggestions....
3. Know you may fail sometimes but don't use it as an excuse to keep sinning, pick yourself up, dust off and keep walking away from pornography...you have to "starve" this unhealthy lustful spirit out of you....so don't indulge thoughts/actions but cast it down and burn it out with the blood of Jesus.
4. Avoid certain times where you are alone, my friend would stay up most nights till 2-3am watching this crap....and come to school and tell me how awful he felt....the answer was to avoid these temptation times on the internet and go to bed earlier 11 pm. It helped him get over it.
5. Remind yourself...and let's be blunt....is it really all that interesting to look at some other person's genitals? I mean sure the opposite sex has a different type but really it's not that interesting if you think about it.....porn at the root is childish...society drums up sex to be some god and oversexualizes everything....sex is healthy in marriage....but is not meant to be worshipped/sole focus of one's existence....if you read in the OT....that's why God hated Baal worship not only because of idolatry but because of he lewd acts they committed in worshipping Baal. It was mocking the gift of sex God has given to mankind to only enjoy in marriage not outside of it....and also remember it's a form of mental/heart fornication although not physical....(Jesus said if you look at a woman with lust it's committing adultery in the heart). You don't want to make women an object/piece of meat, porn will destroy your viewpoint of women, and not take care of your future wife, instead of viewing them as an individual you should cherish, you will view them as an object of pleasure which is wrong.....
if you think about it....you could do so much more interesting/self-improving things on the internet...such as read about new technologies, news, your hobbies etc....
I hope this helps, but the most important thing to do is confess your sin to God and ask for His help daily in overcoming this addiction.
Suicide is a sin. It's the coward's way out and it's a permanent solution to a temporary problem. God never gives up on you. Don't give up on him. 
