Recurring depressions getting worse. Suggestions to beat it?

I've tried everything I can think of from diet changes, drugs (Rx), alcohol, physical activity, work, staying near people, staying away from people, etc etc. I still find myself contemplating my own death everytime I lay down to go to bed. I'm not trying to sound dramatic. I am a 22 year old college student who has had a successful (relatively) life so far.

I've been getting debilitatingly depressed once a year every year since 2007. I thought it was just teen angst for the longest time and just let it go. It's been getting progressively worse every year until even my closest friends and family members have told me that I'm not my 4 months out of the year. This 2012 round of depression has been going on since December of 2011, with no end in sight. I'm worried.

A lot of emotional, financial, and otherwise bad things have happened, all during the initial round of "I hate life" and I feel like they have fed into my depression to the point I fear for my ability to get out. Is this unique, or have any of you beat this before? I'm pretty sure I'll be depressed every year for life, and I'm okay with that if I can control it to an extent, right now it's out of control. Anyone have suggestions?

TL;DR - I get depressed every year, this one's really bad, need suggestions. Tried a lot of things already.