I'm about to be a senior in college, I don't know what to do with my life and I'm very unhappy. What can I do?

It's taken me three years in college to figure out what my major is going to be. I have changed it 7 times, and now I'm doing a self design major in religion and culture. But I don't know what I'm going to do with this, and in addition, I don't know what I'm going to do with my life. I really don't have any dreams or ambitions. On top of all that, I really hate my school -- but I can't afford to take a leave of absence or defer because it would end up costing me money and delay my graduation. I feel really screwed up and depressed because it's been one horrible year after another, and I feel like I've had no guidance from my advisors (because I haven't -- they've either been 20 minutes late or they've forgotten). I feel like I'm stuck at a dead end. My senior year is going to be the most difficult because I was required to create a plan for my senior year that is focused on me continuing on to grad school, etc., etc. The advisor I'm planned to have for next year is ridiculously tough (it seems) and REALLY won't like my decision to pursue something different than was arranged because it will 'reflect negatively on her credibility.' What can I do when I don't know what I'm interested in pursuing, when I don't know what I'm going to do with my life, when I cannot defer or take a year off or transfer, when it's technically my last year of college, and when I'm thoroughly unhappy and extremely depressed? I've lost all hope in myself, and I've declined in my social life, in my self confidence, and my life is falling apart.