In addition to what others have stated (especially the part about making friends without necessarily romance in mind), do not take all the blame for this failed relationship onto yourself. Whether she got a taste for freedom and wanted it back when she went away for the weekend, or something else entirely, this is not all on you. She will have had her own issues. So please keep that foremost in your mind.
Some women are not good at ending a relationship. So they peel the bandaid off slowly. (asking you to move out, agreeing to and then cancelling plans, the gradual cold shoulder, etc) This draws out your pain, unfortunately, and you spend weeks and months second guessing yourself, wondering what YOU did wrong. It tears down the self-esteem. So as Loz said, you need to work on building that back up.
I'm sorry you're hurting. There is nothing wrong with your feelings of hurt; these are natural, and you know that they will pass. Just remember to pick yourself up, and keep living. Consider telling yourself what you would tell a friend in the same situation.
Peace and strength to you,