I know it's really hard. I hope you're feeling ok (as well as you can). I'm sure he is at peace. You will be too soon.
I lost my Missy in February. I had hoped she would pass at home on her pillow, but she was getting worse with her heart problems and it was the best to have her put to sleep quietly. I knew I was going in the room with her and seeing her through this. I hated seeing her at her last moment, but it was all part of having her and loving her so I wanted that last moment to be with me and me with her.
I was so scared and I had heard stories about how they drift off slowly. I didn't want that. But she was so old and sick she left in less about 10 seconds.
That was hard...hard not having more time. If I had had more time I would have spent it wanting more time...and more time.
And like you...when I got home it was quiet...hardly any tears and I wasn't "upset". I have my moments still (kinda like now) where I miss her something awful and I think about her all the time and talk about her and remember her and the silly things she'd do. She's only physically gone in my mind. She's always here somehow. I can still remember her bark and how it felt to touch her head and scratch her ears.
no one can take her from me. And that's part of loving them too...Keeping them with you forever in body or spirit.