I think we've veered way off topic here- for what it's worth to the Op, we are the generation where working hard and mindlessly following the path others followed before us isn't what leads to personal satisfaction. You aren't the only one in this boat, there are plenty of others who feel rather lacking in direction as to what they care about or what they want to achieve.
Whilst I don't necessarily agree with what SylviaB said, there were some harsh truths mentioned in there regarding the generation which looks for that feeling of instant and measurable satisfaction (and hence the rise in popularity of gamification in everything from going for a walk to raising money for charity). Putting that back in the context of the Op, maybe you are looking too hard for the perfect thing which will yield instant satisfaction the moment you identify it when really you might be better off focusing on your strengths (e.g. look at what subjects you did well in?) and seeing if you can leverage that to lead you down a path which will hopefully bring you both money and some degree of satisfaction; or at least enough money to enable you to pursue whatever else you might have a passion for.
Just my 2c.