It could be...
It might be from the repetitive motion on your parts, and the 56 mile ride was the thing that sent the situation over the edge. Get your new saddle quickly!
I had a similar situation, a few years ago now, where I scheduled my annual exam a little early because of this type of situation. My doctor was really puzzled by the "lesion," as she called it, but after talking with her, I knew right away it was from my saddle. I was in constant pain and didn't know any better. While I still am sensitive in this area, especially when it's hot out, changing to my saddle pretty much cured the situation.
Ouch.