I am so very sorry for your loss of your darling Roxy. I was in tears reading your post because so much of what you experienced also echoed the road I've walked as well. You made the right decision.
For me, after, there is nothing but grief for a great long while. Even knowing I did the right thing, to grant my beloved darlings that final decision, that final Grace, that last gift I could give them of peace and freedom from pain, wasn't comforting because at the end of it, it was my decision to end a life--it was the right decision at the right time, but bestowing that final Grace to let them go, is carried with me forever. I had to do this for my beloved dogs, in order to be kind to them. Like you, I choose private cremation, so I can take them with me if I move. I've also looked into that "galaxy swirl" type of jewelry that would have some of my babies' ashes in a pendant. Peace to us all.
Heaven is the place where all the dogs you've ever loved come to greet you.