It is physical isn't it?
TBH I don't really know how I managed the first 24 months - it's all just a blur.
I was very fit and healthy when I got pregnant, but had mild SPD when pregnant, a horrific and enormous crash section incision, which cut all the nerves and muscles in my abdomen, and I live at the top of a 5 storey building with no lift.
I have no car and I'd walk the mile to the shops and back with DD asleep in her buggy (the only nap she took until she was 18 months when she stopped napping altogether) and then I would heave the buggy with all the bags attached to it up the steps into the hall and carry babe and shopping up the stairs four times to get all the shopping up and into the fridge and freezer. When Dh was not working he'd give me a hand of course, but he often was with clients, and I couldn't leave the groceries in the hall because of business tenants..
I was so wrecked once I saw two old colleagues walking in the park as I pushed the buggy and walked right between them and they didn't recognise me. I just walked on and started sobbing! I was so wrecked looking they didn't know who I was...
Everything changed when DD was happy to climb the stairs on her own so trips to the shops and carrying the groceries up to our apartment only took one ascent. It was about this time when she stopped waking in the night also
that was great.
I still have huge biceps (DD is 6, and carries some of the shopping..) and I laughed a LOT when I overheard a trainer in the gym say that women don't develop muscles.
Something called a HippyChick hipseat carrier helped me when I had to do something with my right arm, and had to hold DD (after she had grown too big for a sling - she's in the top 99 percentile of height for boys).
The hipseat a big belt with a ledge and DD used to perch on it and could see what I was doing. She'd hold on to me and I'd have my arm around her back. Worked well for us and you can rotate it round so that you don't end up too lopsided (if you can use your non dominant arm to do anything useful that is!).
It gets easier when that get older though, and now that I'm (well) past 40, I'm not sure if I'm just crocked with age, and gravity is just winning anyway!!
Tesco have since started to deliver to my area - how I wish they would have done this earlier!