yeah... time is a factor. As time goes by, your strong emotions
will fade eventually. If you have not felt strongly for that
someone, then it was just a fling.
So think good bout it, carry on with life 
Personally, I'd advice a nice cold shower, get a new hobby, get
back old hobbies, meet new friends, bring a good book to a cafe...
the ist goes on. Fnd was to chill and occupy your time. I go to
jazz cafes with a good book to forget things, work and
relationships. So give it a shot 