My fiance is long distance from me, too, and though close enough that we can generally see eachother almost every weekend, there are times when several weeks go by. So
I understand. Time apart is hard.
Will you be able to communicate regularly? Either via phone or e-mail make sure to leave little notes about your day. Things you're doing, things you're looking forward to. And listen about his. It's important to keep connected about the little things.
Then, keep yourself VERY busy. All that stuff you've been putting off. That thing you've been meaning to do or see. Do it now. It'll give you more to talk about to him, too!
Get in extra exercise, spend a little more time with friends, or your family. Just keep busy, and keep communication open
You'll make it through this time.