What do you do if you miss someone terribly?

Missing someone you love is tough, but don't waste your life wallowing. Keep busy and distract yourself by taking up a hobby, exercising or hanging out with friends. The less time you are alone the better. Usually when you are alone you will miss someone more. If possible, call the person whenever you miss them. Just keep them in your thoughts but don't let it hurt you too much. If you have a picture of them, keep it with you and look at it whenever you miss seeing their face.