Sometimes when I have 20 tubs to clean after work I feel like that. And get the same feeling once I start and start handling all the animals and see their growth and health. It never gets old. So I can totally relate in that aspect. As for the animals passing that can be very difficult. I just try to keep in mind that under my care my animals have had the best opportunity for a great life. Last year my 16 yo dog passed and it was very difficult. But I sat back and I thought that at least while he was with me I gave him the best life that I could have. Hopefully that helps you also.
Sean