Selling yourself short.

It means you still have more to learn about yourself, and I personally believe the best way to do this is to force yourself into new situations. Watch the movie "yes man", it's a little sporadic at times and loves the idea of fate, but there's an adventurous life changing principle in there. Experience. Say yes! To do what you want to do, you first have to know what you want to do. Clearly there is more you want to do, so find out what it is. Be more analytical of yourself and your actions, and ask yourself questions like "what have I done today?", "what am I proud of today?", "where could I have done better?", "if I had another hour in that situation, what would I have done", etc. Try out different religions, meditate, go yoga, do some charity work, surprise your wife with crazy romantic gestures, read a book that you'd never think about reading, buy a telescope and watch the stars. Hopefully among all the new things you try out, you will find something that captures your imagination and dreams, pushing you to pursue it further and further until you are satisfied that you have done something great.