Has anyone gone through a divorce/deployment with their dog?

Hi all, I need some advice. Anyone can give input but this is mainly for those who've gone through major lifestyle upheavals with their dogs...I mentioned divorce or deployment, but what I'm getting at is a situation where someone in the household whom the dog has grown up with leaves. My fiance left for military basic training 3 weeks ago and my 12 month old brittany has reacted to it terribly. It is almost like someone came in the middle of the night and swapped my dog for a completely different one. I don't know how else to describe it without getting into sordid details, but suffice it to say that before Chris left she was the most easy-going, happy-go-lucky dog I've ever met, nothing scared her at all. She rolled with the punches.

Now, she cries constantly. She's glued to my side and has mild separation anxiety. She's full of nervous, hyperactive energy. She now has a fireworks phobia, and since that developed any loud noises terrify her. I come to find out today that she is now afriad of being in the car, when she used to love car rides. I don't know how to describe it other than she she seems to be hyperaware of her surroundings and often exhibits almost frantic behavior.

She gets 3 walks per day, at least a mile on each. I take her to dog parks to play and to the animal hospital where I work. She is well-trained and obedient. I've kept her schedule as consistent as humanly possible since Chris has been gone, and as far as I know, she lacks for nothing. Has anyone else gone through this with their dog?! I'm at a complete loss at this point. For awhile I was trying to chalk it up to her age and the stress of a very new situation, but things don't seem to be improving, they seem to be escalating.

Any advice any of ya'll can give will be so welcome. I'm sitting up at work at lunch practically in tears because I feel so completely helpless. Thanks.