I think Blackstone's reply makes a lot of sense. While it is normal to feel a small amount of loneliness when your YF leaves you because it is natural to miss him, it may be quite unhealthy if you are severely depressed when he leaves. I have to confess, I used to feel really depressed like that when my YF would leave me after a weekend being together. There was one thing that I found that did help a lot, though. I had other adult friends and I would involve myself with them when I wasn't with my YF. In fact, I would involve myself with them even when I was with my YF sometimes. That helped to ballance things out and made temporary seperation a lot easier. It is never fun to be temporarily seperated from the one you love, but you can help yourself and keep yourself from sinking into a depression that may actually be harmful. Try to keep in mind that although he is a very important part of your life, he isn't your whole life....or at least he shouldn't be your whole life.