*Has it been getting steadily worse?
*Does it hurt like hell if you step on a rock (or something similar)?
*Does it kind of hurt more right after you finish a walk.....but then gets a bit better?
Stress fracture? I've had one myself.....but back when I was running a lot.
I'm not sure if I'd says it's gotten steadily worse. Some days are worse than others and it had been worse recently compared with a month ago (at least from what I can remember).
It doesn't hurt when I step on a rock, but since it's been hurting, I have been walking more cautiously so I don't step funny and twist my ankle or something.
It usually hurts more when I've been walking more, but not always right away when I stop. It might start hurting an hour or two after I stop walking or if I stop for a rest. Prior to a week ago, I'd kind of take it easy if it was hurting (like crossing my legs with the injured food on top rather than on the bottom and shifting my weight to my good foot when cooking or doing dishes), but the last week I've been elevating most of the day it if it hurt that day or the day before.
When I remember this starting, DH and I were on holiday in Germany and doing a lot of walking/hiking but I don't remember hurting it or stepping funny on any walks. About a week before we left, DH dropped a 400ml bottle of water on my foot (landed on the top of my foot, not my toes). I hope that's not the cause, but it's the only unusual thing I can think of!