Making Sense: Finding the Pieces

I am coming up on my last week of teaching English for a year in Korea. It has been trying and difficult and although I've hated nearly every minute of it, I'm finding myself very scared to leave and try something new. Although I've struggled and strained and snapped several times, I'm finding it very hard to let go and move into the unknown. I'm leaving in a week to go trekking in the Himalayas. I should be excited. I love hiking. I've often said throughout this past year that all I want to do is hike and just keep hiking and be outside and keep hiking. And now that I'm going to do it, I'm frightened. Is it because of my lack of research and planning? I really don't know what to expect or what I'm getting myself into. Is it my lack of self confidence? Can I really do this? Will I be any good at it? Can I learn? Or was it my inability to decide for myself what I wanted? Or did I decide and am I having a difficult time accepting the fact that I can make a decision and that my decision will be OK because I will make it that way?