You just said goodbye. He or she has just walked out the door. For good. This part is never easy.
Your first instinct might be to run after them and beg them to stay, but we'd suggest that you take a deep breath and give that fleeting moment a chance to die down. The pain will not last, we promise. Instead, here are some songs that might help you turn the page, reflect a bit deeper, and perhaps find your inner strength to live without that person.