Just need to vent

I started my job training at a veterinary clinic today and within the first 5-6 hours of working we had euthanized 3 pets, now they were very old and had a very poor quality of life so I fully understood why each owner wanted to do it. But it was just very overwhelming to go through all that on my first day. I helped with one and shadowed the other two, the one I helped with the owner opted out of being in the room and it honestly broke my heart into pieces for that sweet girl.