I have found that obsession calls for more obsession, at least for me. What works for me if I'm too focused on someone is to take a step back and do something else, about me if possible. Read a book, play a game, do a hobby, watch a show... Something to take your mind off of that person. Try not to think about her when you're apart, when you catch yourself doing so, grab a list of activities you enjoy and pick one from the list, or call friends and go out to movies or something.
You're not going to stop loving her (and neither do you want to, anyways!), but it should snowball less, if you're anything like me, and that might help you.