I too was in an LDR that required an 8 hr drive; fortunately my BF flew which cut his travel time down immensely. Helpful as that was, I still dealt with the difficulties of the distance- of him being gone. What I know now is that part of my difficulties were that I had abandoned alot of myself for him/the relationship (even before he left) which actually has impacted me for many many years now.
As trite as it sounds, distraction, is truly the best medicine- getting and keeping yourself involved in various activites and building/creating/keeping your social life moving. Use this time to really get to know yourself and to bring out those attributes you like about yourself most.
My tools program just hit on the topic of 'being complete' and how if there is a gap, then we will get hung up, whenver that gap catches upon the gap of another. And, in this case whether the gap is the physical distance or the emotional, it is something to indeed work on/toward.
Do you and your BF have regularly scheduled visits? Are you remaining committed (ie exclusive) to each other? Is this that the best option for each of you? What forms of communication are you using- today with the net and ipods/phones there are a ton of options.. which are you using?
Basically, focus on making your life about you, it will allow you to bring so so much more into your relationship with him and give your relationship a much healthier foundation.
If you don't know where to start, go back to your childhood and look at which things brought you joy then go renew those in your world today- go ahead and play again- let loose; let go of life being all business all formality all about moving forward build fun time/you time/learning time/travel time/ creative time into it.
If you focus on you while respecting the relationship it will survive and it will be 'the' relationship that you would want to make forever... if you make the relationship your focus, you will find plenty of hurdles to be faced down the road.
Make yourself complete and bring your whole self to it, you and your guy will be enriched in ways you are not fathoming now.
(Even being creative through art/prose/poems/ etc about how you are coping will be a release and gift to yourself)
I know its hard to put this into action. If you are dealing with serious depression, (I hit my absolute lowest at this time), get yourself some help do not let this take you down- if it is, then you definitely need to do the work to bring yourself back around. Learning to be whole without others is something that is a MUST in this life... it has taken me far too long to understand this is key to happiness- nothing else will get you there.
My best to you; these are trying times, but also awakening times... look at your world with new eyes and go explore.