I really do care, so please, please, please don't kill yourself. Even if it seems like you will be, you won't stay in this slump forever if you really want to change, so please don't get rid of any chance of success you have by committing suicide.
Traveling will be kind of scary, even with friends. Going there alone might actually help you out a lot. I went last month and everyone is really friendly and there are TONS of things to do, and if you stay at a hostel it will be even easier to meet people to hang out with. Many groups that stay there are really laid back and will invite many people to just tag along. It's a great experience.
I think, also, that sometimes you don't always have to have an interest in what you do. You say you have no interest in working or doing anything, but I would at least TRY something with an open mind. Even if you end up hating the activity, it will let you meet new people and it might even open you up to new activities that you will enjoy. Just pick something and try it for a while, whether it be a part-time job, going to a group in your town, or anything of that sort. Just try. But, don't go into it thinking: "I hate this, this is going to be boring, I don't have an interest in this." Say: "Okay, I could like this so I'll do my best while I'm here."
If you're relying on your parents for everything (I'm assuming? you said you live with them still) then it's really not fair to them at all to have to support you totally for this long. Even if money is no object to you, they're still having to work for it, right?
But, I think something important has to be addressed first:
Do you WANT to change?
If you want to, then heed all the advice that everyone is giving you, because I know you'll be able to succeed.
But right now it sounds like you're making excuses to everyone in order to keep from trying anything. We don't care why you got this way and we're not judging at all, so excuses aren't necessary. If you want to be able to go out and change yourself, then we're all here to help you find ways to do that.
But, if you don't want to change and you want to stay in the exact same situation, then tell us that, too, because it's unfair if people are genuinely trying to help you, although you know you'll just reject everything they say.
So, do you want to?