This is the exact thing that I'm going through right now so I can completely empathize with you, Aida. My boyfriend of two years with whom I was living for nearly a year, recently moved out to another city for a new job.This decision was agreed upon by both of us so I can't blame him for taking the job. It's a struggle every single day to function with thought of losing him constantly nagging at the back of my mind. But like some have said, communication and effort are the two things that can help you tide over this situation.
What the two of us make it a point to do is text each other whenever we can or feel like, irrespective of whether the other person is available on the other end or not. Some times if I wake up in the middle of the night and start missing him horribly, I just text him and tell him exactly how I feel and how I wish he were there. Sometimes I wake up to find similar texts waiting for me in my inbox. These are the moments we both live for while being away from each other. Apart from this, we talk on Skype whenever possible. Some nights we just keep the video chat on and watch each other sleep off and wake up in the morning to find our faces frozen in really funny positions! We also send each other pictures from our daily lives - food I cooked, or a book I'm reading, or something that I bought, or even a pimple that may have grown on my nose! I make it a point to tell him most of the things that I did in the day, ask him for his opinions about things that I'm doing, just to make him feel involved in my life despite the distance. He does the same.
It's only been a little over a week for me into this form of long distance relationship. I'm as worried about us as any body would be. But the above mentioned things are just some of the little ways in which we try to stay connected and close, despite the distance, till we meet again.