keep yourself busy, talk to him, look at pictures of him and you if needed, and dont drown yourself out with negative thoughts! me and my boyfriend are separated on occasion for a certain part of the year and its hard; theres no doubt about that.
it dawned on me a couple of months ago that our relationship is a long distance relationship and it really threw me for a tizzy! there were days when i just wanted to cry my eyes out and give up! but, i refused to let a little distance break us up. im still "recovering" from that realization to this point, but it has made me a stronger person and really helped me to remember why i love him, fell in love with him, care for him, and want to be with him. im a religious man so i find that helps me out.
but keep yourself busy and dont listen to the naysayers who say that such relationships dont work out! imagine what married couples have to go through; im sure there are couples out there who feel like giving up because it seems so insurmountable!
as others have said, remember the good times, the times you will have, and the connection and relationship you have with that person. and while it is hard to go without sex with the one you love and care about, the waiting does make it all the more special, as well as the kissing, holding hands, hugging, cuddling, and so on!
YOU WILL MAKE IT THROUGH!