A year ago tomorrow was also my last day as Youth Pastor (in Indiana; their choice).
Transitions are never easy, but- and I had a friend tell me this last year- these kids and this congregation have gleaned what they needed to from me, and there are others out there who need me now. At the same time, there's another youth pastor out there with a calling in these kids' lives, in this church's life- God's been preparing them for that role, and they're ready. It's time.
In college, I remembered writing in a paper that you knew the health of your ministry by whether or not it could survive without you. If it can't, it's not pointing to the right person. If it can, to God be the glory.