Did you take a pre and/or post boil gravity reading? That will tell you if you had any conversion.
After mashing that high, It will likely have a sweet finish, but without knowing the original gravity, we can't tell you much more than that.
Was this on an electric stove top? If so, remove from heat (move to unused burner) once you hit your target temp. Those electric stoves retain and continue to transfer a bit of heat after they're turned off.
Edit: To answer your question(s): Patience. 18 hours is nothing, but a 1/2 pack of yeast will take care of it in no time. I personally don't think it's worth the risk to save dry yeast, but I know others have.