Low sodium levels

Is there anyone who was told they have LOW sodium levels?  My weakness has always been salt vs. sweet.  I would choose salt.  I salt food now, but apparently my level is low.  First my kidney levels were down, but today they are OK.  Now it is low sodium. 

I am 4.5 months post-surgery and I have lost 68 pounds.

My dietician said my sodium levels were a bit low and that it was probably from drinking too much fluid and she told me not to be scared to salt my food to counteract this.