It is so sad to loose a pet. Two of the cats I grew up with were killed at 16 and 18 by the milkman's dog. I was on holiday with friends (early 20's) when I phoned home and my mum told me. I was a complete baby and broke down in the telephone centre, stupid friend told me to pull myself together. It's not that easy when you have had, and loved, them for so many years.
I adopted two cats when my brother moved. We were looking after my Nana's schz-oo (def a sic) and we got home from the DIY store to see the oldest cat dead on the carpet (I don't want to know the injuries he sustained). I was 7 months pregnant at the time, but ran hysterically out of the house. The neighbours were brilliant, but I felt really guilty afterwards as one of them had lost his seven year old son the year before.
I hope you feel better soon.
