awww shell you definitly have a sucky month ahead of you! I hope this doens't get you down and you'll soon return to your bubbly self.. although its completely understandable why this could take time.
As for shanes birthday and conserving money you could always take him out to his fave resturant, cook his fave meal, make a mix tape of the songs you love as a couple, make a cute little scrapbook with all your favorite pics, and you could take the opportunity when he's gone to make those so he'll never find out until the big day.