How do people with signifigant others stay strong while theyre deployed?

My boyfriend of five years got deployed to the Dominican republic two days ago. I thought this was going to be easy, seeing its just a peace mission and only a few weeks but its harder then expected. He called me when he was boarding the plane there and said he would email me ASAP to let me know he got there ok. I havnt heard from him yet .. and although I'm sure he's ok its hard to deal with. Anyone have any advise on how to stay strong or what to do? It's hard to sleep. Any advise would help a ton!