Welcome to SR, I am sorry you have been hurt but if you take a good read around, being dumped was probably one of those strangely wrapped gifts that come our way in life.
There is no happy ending for a relationship that includes active addiction.
Go home for the summer, try to heal from this sadness, and then do everything you can to move on with your life. There is nothing good to be found in this relationship, and you have a chance to make a better life for yourself, please take it.