What were you doing yesterday?
I've gotten a cramp like that in my right leg/foot while driving my car after a long bike ride and then putting on compression socks. Or with regular socks but sneakers tied too tight. Pulling over and removing the sock/loosening the shoe solved the problem. I assumed the muscle was tired from all that pedaling and then not reacting well to the combination of pressure on top of my foot while flexing my foot at the angle required for driving.