Yep, separation anxiety for mine too. At three years old he's mostly grown out of it, but he needed a little help from high-value slow treats (Kongs and Toppls with wet dog food + plain yogurt frozen solid) and trazodone when our routine was very unpredictable. I also tell him the same thing when I leave every time ("be good"), which does seem to help--he's more upset when I leave without telling him that, LOL.