This is life. Some things strat, some end. We should not regret. Future will bring you something new and inspiring. To live means to change. Day after night, spring after winter. Death after life and then...live again! :) It is OK to be sad, but you are not losing anything because you don't owe anything. We are just walking trough our lives, our path.
Here is a saying: when you come to earth you have a body and soul. During your life you gather some belongings. When you die you left a body and belongings. So what do we realy HAVE? A soul! An experience! What you have - you have. You cannot lose anything that is material, it only comes and goes when curcumstances change ...Your soul had experienced every moment here in Bulgaria, it is in your mind, your memories...so you cannot lose it :)
Cheer up!