Mid life crisis!

19 months into my Phd and it suddenly hits me that I still don't have any clue of what I am doing here. Things are even more unclear than it was before I came here. and no fancy aspirations attract me these days...and the world around me seems to be rushing to the finish line. Despite not knowing what awaits them there, I still feel left out. Friends are getting married, people are settling down in life and my life seems to be stuck to 14/06 and gtalk. No aspirations, no sense of achievement and life seeming to worsen day by day...I now understand what mid life crisis is, despite having not even reached 30!