My 1 yr old Fred has issues with stress, we had a major fireworks show in town in July, he spent 3 days at an out of town vet due to becoming very lethargic and not eating.. After that he seemed fine, then his mommy (my neighbor has his mom Gypsi, they are best friends) became pregnant and he seemed ok until 2 weeks ago when the pups were born, he quit eating and just seems so sad

This last weekend we had a little bout with vommiting and diarhea (We this that was due to some new treats we had gotten), that has subsided and everything is back to normal, except the eating which finally today is coming back a little, which does concern me a little cuz he has lost almost half a pound his normal weight is 2.3 lbs.
Anyway he is still just not Fred, hes not jumping like crazy running around the house like Fred does.. I am just wondering has anyone else had a yorkie like this who seems to stress at change? If you have how long did it take to come back to normal.
I know I am not on the boards alot, thank you for any advice..