Insanity

I'm about to lose my mind over this. I didn't know where else to post this, so I put it here, because it seems I'm a beginner at this. I have this problem, and it's nearly driven me to giving up music -- the one thing that makes me feel safe.

I can't get what's in my head, onto my guitar. I hear it in my head, and I go to play the first note/chord on my guitar (almost always wrong), and as soon as I do, whatever I had in my head shatters. The actual physical sound of the note overpowers whatever I'm hearing inside my head. So I'm stuck with some note or chord I never intended to play in the first place. I can't seem to compare what's in my head and what sound my guitar's making.

I've been writing music for about three of the seven years I've played, but in a very specific and unsatisfactory way. I play around on my guitar, playing random chords and notes until I find some that go together, and then form them into some sort of song. In the beginning the results were really interesting -- even pleasing -- but after fumbling around in the dark for three years with no idea what I'm doing, I'm sick of it.

Everything I write in this way now sounds cluttered and messy; like it wants to be something, but isn't quite actualized. I don't care about anything I write anymore. It's like trying to spell without actually knowing any letters. It's gotten to the point where I've deleted all of my recordings from the last three years (literally around 200 including clips and ideas).

I've tried learning relative pitch, and even perfect pitch, but for some reason, my mind can't seem to remember the sound of a particular interval, whether it be a fourth, fifth... whatever. I've spent hours and weeks, but I can't seem to get it. This is affecting every part of my life, and in an extremely negative way; everything seems so futile now.

I'm extremely creative, and I have no problem hearing and creating music in my head, but I just can't get it out.

I know part of the problem is diligence, but I hate admitting it, because then it just seems like I don't really care enough, or that I'm not really trying. I feel like I've lost my passion and I'll never again be able to find it. I need help; please.