I've had a lot of these moments recently, and I want to hear yours. It's not a bad moment for me, either, because while it is inconvenient to not be able to do as much physically, it's a huge relief and excitement to have yet another sign that my hormones are actually doing their work.
Yesterday, I had band practice, and after I decided to pack up a section of my keyboard setup at the studio and bring it to my apartment. It's been there since last spring, and I've been on hormones since February - so it's been a while since I've moved it, and when I last moved it I was working out a lot in preparation for summer and working with a charter boat company.
It used to be no biggie to lug that setup from my car to my 2nd floor apartment (really glad I'm not a 4th floor person right now, lol). It was just a keyboard in a soft case I have, the keyboard stand (a Z stand that can hold up to 600 pounds, so it's fairly heavy for a keyboard stand), a backpack full of cables, pedals, and other random music gear, and my main bass (a J-Bass I built). Not really that much gear, and I used to be able to carry it around no problem.
Now, it's the day after I carried that stuff up to my apartment, and my muscles are sore like they used to be when I'd -actually- work out really hard. It's blowing my mind that just taking that gear upstairs, that I'd have done without a second thought before, now causes me to have sore muscles the next day, just from taking it up to my apartment.
I have a collapsible hand-truck, so I'm just going to use that for moving more than I used to. I used to just use it for larger speaker cabinets (4x10s or 8x10s usually), but now that use will be expanding haha.
This is just another thing that's happened since I started hormones that's told me this is the right track. Have any of you had similar things happen - did you have a moment, after starting hormones, when you realized you really are losing muscle mass and strength, and gotten excited about it because of it being evidence that your HRT is working on lowering your muscle mass?