it always seems that people strive for a sense of purpose in life, i guess it's what keeps them going. they allow the pursuit to define who they are. in the hedonistic vein, I say, do whatever feels right, whatever you have a passion for..as long as it doesn't consume you in a way that harms you or others close to you; and always, learn from it.
feeling the need to be a productive member of society is basically spinning your wheels; unless that's what drives you (living for other people), avoid this mentality. it may leave you miserable. some people devote their lives for this purpose, good for them; they chose that path.
don't try to compare your path to theirs, it's moot and irrelevant.