I really struggled today

I could have lied, but then what would be the point of the blog.
All I set out to do was a 5km walk. Nothing I haven't done before, nothing too fast, just to cover the  distance today and hopefully stay below 12 min/km.
But I ended up turning back after 3.7km! I have no idea what it was.  My hips were hurting and my legs started to get shaky.
Before leaving, I had changed the innersoles of my runners to a new pair of orthotic ones I bought. Could that be it?
I've used custom made orthotics before, and suffered some achy joints as I got used to them, but nothing like this.
Or could it be the running from yesterday, maybe my body is still recovering, even though it was only 3 minutes running at a time and I've done it before.
The only other thing I thought of is the iron tablet. I'm supposed to take one every day, but rarely remember. Otherwise, maybe my body is just trying to con me into stopping - or my mind for that matter!
I just don't know. But I'm leaning towards the innersoles.
So we will see how it goes tomorrow. I am supposed to to do C25K W3D2 tomorrow, but I will try hard to listen to my body, without just making excuses. There is always Friday if tomorrow doesn't work out.

On a more exciting note, only 3.5km to go till I get to Sawn Rocks on my Virtual walk/run of Australia. As the goal was to get there by the end of January, not a moment too soon :) I'm sure I will at least be able to walk 3.5km tomorrow, then on to my chosen reward - a drive out to Sawn Rocks for some photos this weekend!!
Total Walked/Run since 1 January 2013 = 51.7km.