Not just 'carefully', he was litterally picking one foot up, stretching it straight out and dragging himself along, a literal hobble. He'd stand and sort of shake, he tripped from a standstill.
All four legs, though one of his hinds felt tender around the knee area.
What is going on?
We called a vet, over the phone he said it sounded like he was just getting used to his feet, but this is extreme, and he was fine with a few little trips yesterday, THAT is what I call getting used to his feet.
Note: this was on the gravel and sand, grass he was better, still ouchy but a little better.