Not Looking Good..

I've become pretty worried recently that I may be developing Schizophrenia. Based on the symptoms I've seen listed, much of what I'm experiencing seems to be attributed to Schizophrenia. I'm just looking for some opinions, or perhaps some advice on the situation.

I'm 18 years old, and for about 5 years or so I've been dealing with depression, though I have never been diagnosed with a specific illness. They have called it Major depression, and they have called it Bi-polar, however my symptoms have never quite matched up with either. There is a history of mental illness in my family.

That being said, about 2 weeks ago I smoked a lot of marijuana, and since then strange things have been happening, and thinking back more minor things were happening before I smoked. I had always become moody after the high of smoking wore off, but nothing more. I think the easiest way to do this is to just list off some of the things I have been experiencing, which I believe can be attributed to Schizophrenia.

-Fear of the dark
I haven't been afraid of the dark for as long as I can remember, yet suddenly I panic every time I am in the dark alone, or have my back to a dark room.

-Songs CONSTANTLY playing in my head
I know it's normal to have a song stuck in your head, but I have had to turn on a radio a couple of times, just so a song wouldn't be running through my head. The songs change, and are sometimes songs I can't even remember hearing.

-Fear of some unseen beings (Generally associated with the dark)
I keep feeling as if there are small child-like beings watching me from dark rooms. This happens in flashes, as I think about it right now, it seems silly, but when the fear sets in it is the most realistic thing in the world. I have found myself turning on every light in the house and locking myself in my computer room to avoid this.

-Scattered thoughts
My thoughts seem to race around in my head at certain times, where I'm unable to focus on any one thing. I have had a stranger recently comment this, wondering if I had ADD

-Zoning out
I have often just stopped what I was doing to stare off into space. This morning I laid in my bed for about 3 hours just looking around the room, not really thinking about anything.

-Faulty memory
I have forgotten conversations, and questions that have already been answered to me

-Missing work
I didn't go to work today, and I'm not too sure why. I just ended up laying in bed, as noted above.

-Perception changes, inanimate objects appearing to move
As I was laying in bed this morning I found myself looking at the corners of the room, the corners seemed to flip in and out quite like an optical illusion using a cubic shape. I have a couple of times noticed things moving slightly, or vibrating that shouldn't be.

-Thinking that someone can read my thoughts
I have thought that a co-worker was reading my thoughts, and plotting to have me fired. I attempted a protective spiritual meditation to defend against this. I have also thought that the child-like beings can read my thoughts, and sense my fear of them.

-Thinking that co-workers are talking behind my back, actually leading to a brief confrontation where such was denied.

-Paranoia/doubts in my long-term girlfriend.

-Mood swings
I have always had constant ups and downs, but it seems to have gone to another level. I become aggrivated, or sad, or happy more rapidly than ever, and with less cause.

There are quite a few more minor points that I could make, but I think that that is enough to work with. I myself have come to the conclusion that I am developing schizophrenia, or something like it, and plan on seeing my psychiatrist soon. I would however like to hear other peoples' opinons and advice as well. I will also make a quit note that I was at one point prescribed the anti-psychotic Zyprexa, as a "mood-stabilizer". I am wondering if maybe the doctor who prescribed me that had an early hunch based on my mood pattern?