Now what?

I recently got together with some friends from college and as I looked around I realized that I was the only one who didn't work full time.  And many of them not only work, but have successful, fulfilling careers.  And I was jealous.  Jealous and sad and left feeling like I've wasted my intelligence, my education, and years of my life. 

I made a choice not to work full time.  To work a job, not a career.  To spend as much time as possible with my children when they were young.  I will never regret that decision.  But now that they're growing I'm left with this huge, inescapable question-

Now what? 

My youngest will be off to school part time in the fall and I am already starting to feel a bit lost.  What do I do when my kids are in school all day?  I know they will still need me, but it won't be the same as it was when they were toddlers.  What will I do all day when I'm home by myself, when my reasons for being at home are no longer there? 

I've been struggling a lot lately trying to figure out what I was meant to do with my life.  I know I can find places to volunteer and things to do to fill my time, but the bigger question is what can I do that will be fulfilling for me?  What was I designed to do?  What would I be excited to do everyday, that would make the hours just fly by, and that I will leave feeling filled?  And the thing is, even after 35 years of life-

I don't know.

I really, truly don't know.  I know what I enjoy doing, but those things aren't necessarily the things that I'm good at.  And I know what I'm good at, but I don't always enjoy those.  If only those two things always hand in hand... I'd be an awesome singer/photographer if only I had the talent ;-).

I've often heard the quote:
"Choose a job you love, and you will never have to work a day in your life."

Great concept.  And that's what I want. 
If only I knew how to find it.