I feel for you...im bout to be leaving my gf yet again friday....like your bf im doing a short 10day holiday over here in the UK, then back off to the states. We got our longest gap if distance right around the corner, not sure when exactly we will see each other again..not looking forward to that. She just started up Uni placement today so i wont be seeing her all day like last few.
You got 7months to get married, and i have 7 months till i move here for Uni...so again i feel your pain! Im mentally done here in the states, just want to fast forward and start my life here and finish school. So these next months are gonna be rough.
Try to stay busy in any way possible, i was fortunate last time i left to be engulfed in school and work. This time around not going to be as busy, only got work...so we shall see! Im here anytime you want to talk, try to stay strong.