Hi..Try to move on from this miserable situation. Only you yourself can bring you out of it. No harm in taking antidepressant after consulting a psychiatrist if condition is really worrisome and hampering your daily activity. In sad mood person remembers bad memories of life more frequently. Stop talking her and if there is no alternate then no need to keep any false hope. Focus your attention in rebuilding your life by meditation , yoga , exercise, watching movies, reading magazines,  studying, talking to your friends. Try not to remember her and plz dont keep any grudge for her. You need to forget her and keeping both type of  emotions like love and hate always keep you remind her. So forgive her.  Discard all her gifts and any kind of belonging which likely to remind her .Anyway consultation with a psychiatrist as soon as possible to be kept on priority. Good luck.