You have just suffered a breakup that you were never even expecting. She simply dumped you on your face in your apartment and moved out with her own friends and the reason she gave you was something vague and never before heard by you. Well rest assured she has been cooking this up for long and the love she had for you was lost some time back. This is all in the past but if you still wish to have her back then you must find and answer that suits your requirements on how to get your ex back.
Although every girl is different but they generally all react in the same manner and that is to avoid their exes and never even talk to them again if their exes come begging to them or say those golden words of ‘I Love You’. Avoid this and also avoid being too nice with her. Furthermore, show her that it was easy for you to move on too and that you are happy that she finally feels better off without you.