I actually think this is a Rough Earth Snake. Picture matches perfectly, size, actions, and habitat. I really had never heard of this little snake. Once, however, as a girl, we were digging worms for fishing. It was just in a gray water area in our pasture where our sinks and washers drained so it grew nice earthworms. I found this lovely fat earthworm and had it lying in my hand closely observing it…it stuck its forked tongue out at me… I dropped the snake and quit digging worms. I thought about that when I found this little snake and tonight researching this I realize this must be the same kind of snake. According to the info this little fellow was a fully mature rough earth snake eating earthworms, slugs, ant larvae, etc.
A better photo of Rough Earth Snake