Here's the secret: motivation only kicks in AFTER you start doing something. If you're waiting around for motivation to come out of the blue you'll be disappointed.

So just start doing something. Choose one that appeals to you: help another person, create something, build friendships. You've spent enough time improving yourself through education, now it's time to focus outwards and give back.

Second, structure. Set some recurring reminders for starting. In the past I have used a dark trick: I asked a friend to be my "demotivator". His job was to knock me off track. If I didn't meet my personal commitment on a given day I would pay him $50. It worked extremely well.