Whew! Glad you took that rest on Sunday. Monday sounded like a challenge! As my knee gets better, and I'm more active, my back has been giving me some pain, too. This is a very old injury site from my 20s, so I'm well acquainted with it. Sitting and standing still always seem to aggravate it. I've been working on an editing job lately, so have been sitting at the computer for long days--and I had forgotten, but it's a killer. I hope your short walk works out some of your kinks!
I've been struggling with that "old lady" feeling, too. I'll just build on something I just said on another thread: For years my body performed ably, and I mostly ignored it. I get irritated that it needs attention and care now. I think that in my mind, taking my good health for granted was a "youthful" thing, and having to make extra doctor visits, to rest and heal, to think before I step, are "old-age" things.
How can we turn that around? Whether we are 50 or 100, we don't really age inside. (Have you ever noticed that?) Refusing the limitations, as you have done, with your 250 cupcakes, is a good start. However, I suspect that our notions of what it means to be "young" or "old" need an overhaul--at least mine do. In the meantime, I keep remembering my dad, who after about the age of 50 had lots of arthritis in his joints. He used to make a visual joke of getting up from a sofa, and he was such a joker anyway that we really didn't realize the pain and difficulty he had. He always seemed young to me, because his attitude toward life had a real joie de vivre.
Or "joke de viper," as my spell check kept changing that last phrase to.
I imagine the wedding and cake items were lovely! What a good friend you are.