just forget about something that we almost had.
This says it all. You almost had it. But you never met, you never talked via phone or skype or anything else. You are obsessing over a 5 month, oh, I don't even know what to call it. It sure was not a "relationship" that you should be obsessing about.
how should I deal with this
Talk to other girls. Find someone local that you can have a real relationship with. You know, like actually being face to face with her? Going on dates? That kind of thing.