I've been in a relationship for about half a year now... and I start to over think if he is "the one". Its not that I don't have feelings for him. I do and there's nothing I don't like about him whatsoever, however, I'm only 18 and I keep over thinking about if he is the one. I'm still young, I should be enjoying this relationship. I do... a lot actually and when I'm with him, texting him or talking to him, all the over thinking disappears, and when I'm missing him (we are long distance)... I start to freak out. I know I shouldn't be. I know I'm too young to think about if he is the one or not. And I do deeply enjoy being with him. Any advice to give me? Its not even a natural thought, its like I'm forcing myself to think about it.

There's nothing 'real' about a LDR. Until you have spent a long time together in person, you can't know if he's the one, and it should be a mutual feeling, gradually turning into discussions about what each of you wants for your futures, and then discussions about what you both agree on about your future together. Although most people have started some talk about the future, it isn't easy to do in a LDR. School and jobs when young often don't allow for plans to live in the same place.

Nothing wrong with wondering although you don't even see each other enough for anything to come of this.
Thinking about a future is not having one so why are you worried about it?