So sorry, furbaby and shepherd and, well, everyone on this thread.
I lost my girl in June. She was my world and she got osteosarcoma - bone cancer. It was the worst thing I think I've ever been through; over the space of 4 weeks she changed from being a happy, lively, wonderful dog, to being dosed up with pain killers and anti inflammatories, and losing the use of her leg, and just looking so sad and tired (and yes, some of that was my projecting my own feelings onto her.)
I got new pup exactly 1 month after losing old girl, although had picked him before I had to have her PTS. It was the only way I could cope with knowing that the end was coming.
Yes I compare him to her, and yes it's been hard, especially as he was so young, and I had the strain of house training, which I never had to do with my girl. But he is so different to her - different size, different temperament. And more than that - he needed me so much. He was 4 months old when he arrived (rescued from Romania and brought over by Action Aid for Animals) and he was so scared after the long journey, and so small, and even despite the lack of training or house training, he needed me so darn much from day one that I had to put my grief to one side for a little while and focus on him.
4 months later I can talk about my old girl without tearing up. I can make the comparisons/discuss the differences and it doesn't feel disloyal. I gave my girl everything I could, and it would be unfair not to do the same for my new boy.
(p.s. your dogs all look gorgeous, furbaby )