The first Unregistered user is wrong. It's obvious that the protagonist has a broken heart over a woman that he may never see again. He regrets whatever happened they led to his loss.
I love the harmonies in this song. They go right to the listener's emotions and heart. His grief is almost palpable. I got goose bumps the first time I heard this song, so long ago when I was in my first round of college. It almost brought me to tears. It still plays with my emotions.