http://en.wikipedia.org/wiki/Buckminster_Fuller#Bankruptcy_a...
"By age 32, Fuller was bankrupt and jobless, living in low-income public housing in Chicago, Illinois. In 1922, Fuller's young daughter Alexandra died from complications from polio and spinal meningitis. Allegedly, he felt responsible and this caused him to drink frequently and to contemplate suicide for a while. He finally chose to embark on "an experiment, to find what a single individual [could] contribute to changing the world and benefiting all humanity.""
You're a young man from Switzerland whose biggest problem (from what you say) is loneliness. Could be worse, don't you think?
Your life is hardly over, it hasn't even begun. Justin Bieber is 19 and has quite a few #1 albums already, should every 20-something singer feel bad about themselves as a result? You need a new yardstick to measure yourself by.
Happiness, whatever that means, peace, it comes from within. You can't succeed your way to it really, money and position will only marginally improve your internal world. Don't conflate the two. My advice is to more accurately attribute your ennui to "wasting your 20s" as in postponing life to when you "make it" - allow yourself to start living now the way you truly want to and enjoy yourself, time goes by fast. You can be happy no matter how things play out, at least happier than you are now, and try your darndest to make your mark all at the same time.
Edit For context : I'm 23 and have been hell bent on "startups" since I was 16 for various reasons. Sometimes I can't sleep because the ol' noggin won't shut off and thoughts fly at a million miles an hour, its a certain feeling that burns you from within. It is a good thing, ride it.