Loneliness occurs when you feel as if nobody gives a crap about what you want. There's nobody to turn to or ask for help, you only have yourself.
Loneliness can make even the happiest of things not seem so great. It really takes most of the enjoyment out of life.
One thing that helps with loneliness is to find a hobby you like and stick with it. Enjoy yourself and have fun while doing it. And if you do it in a club or a group, you might find some nice people who actually give a crap to be friends with.
Also, don't give up on life. Suicide is not the answer. If you're still lonely, then keep trying to find help. Something good might come your way, and death will only take away that chance.
If you keep trying and don't give up, you can surely defeat loneliness.