My sodium level is always low. 133 - 136 . I had a very bad episode also with it falling to 126. I don't eat a lot of salt, but I never have.
I took salt pills to get it back to 133. My Doctor put me on a no free water regimen. It keeps it is stable but still low. I drink very little plain water. If I start feeling bad I take a salt pill or two and it seems to work. I got extremely mental when it gets too low. My body just doesn't process salt well.