In the last few days, my little guy has seemed very nervous. Flinching at certain noises or sudden movements and barking alarmedly at noises he would normally ignore. We have a neighbor in the condo above us who has a really psychotic dog (a Min-Pin), who makes terrible noise tearing up and down the hallways and crashing into things -- I'm beginning to think this racket going on over our heads is causing Archie to get anxious.
I've also noticed over the two years I've had him that he has gone through nervous periods before. Has anyone every experienced this?

Thanks!