I'm not entirely sure if I have anything, because frankly I don't trust my own judgment. It could be typical experience, but it doesn't feel like it.
I'm about eighteen right now, but since I was younger (I can't remember exactly when it began, possibly around 16) I began to experience very unpleasant lows which tended to last up to a few days, and they were far more prevalent than anything else. A "good day" to me is generally a day when nothing significant happens to trigger these feelings, and they are triggered relatively easily. Their intensity runs the gamut from ordinary sadness to an almost crippling feeling when I find it difficult to converse with people. Hypersensitivity is also an issue, as relatively small events could conceivably set me on the wrong track. Talking with others helps, but ineitably I always return tot hat state of hopelessness. There has also been a great deal (multiple times daily) of suicide ideation, though I do not consider it serious planning. I have always entertained it as a last resort, however.
A lot of it does seem to stem from anxieties and insecurities I have. I have for a long time been considered "gifted" and have a long history of academic achievement, but I do not feel as accomplished as I probably should, and I always fear for the worst in my courses. Last semester, I thought I would fail but ended up with almost all As. Over the summer, I had a panic attack at my job working a concession stand, which in retrospect was a relatively minor job.
I also feel chronic feelings of loneliness which my friends can not always solve. There was a bad breakup I had this summer after which I had a drastic change in mindset, becoming far more pessimistic about my love life and almost convinced of its failure. It especially pains me to see others together, and I consider my shyness to be a major obstacle.
There has been a great deal of pessimism that has been a common thread through my life, but recently it has been "legitimized" so to speak. I consider myself a nihilist of sorts, and I have recently been quite vocal in my belief in an inherently hostile world. Most alarmingly, though, I have entertained thoughts justifying my condition as being a means of natural selection, with me being selected out. I know it sounds ridiculous, but at times it has seemed plausible.
I do have something of a history. My father's side of the family has been known to have problems with bipolar disorder and schizophrenia, and I myself was diagnosed with childhood depression in elementary school, as well as ADHD earlier on. I am concerned, as my symptoms have intensified and become more frequent in college, sometimes reaching intolerable levels. I am unsure if this is diagnosable, but dysthymia seems to fit to some degree.
Of course, I can't diagnose you with anything. First of all, it's hard to judge these types of things when you're talking about teenage years, because anyone who has been a teenager knows it sucks, and to a certain extent moodiness in these years is to be expected.
However, if you feel that your issues are enough to be holding you back, impairing your school or work life, your friends, or making you miserable, it's really worth getting checked out at the least. There should be someone at your college that can do a screening- a counselor or something.