No sadness but yes to a general feeling of crapiness. It was temporary (3-4 days). I have pretty bad depression and anxiety problems but LC has improved the depression a lot.
Make sure you're getting 5 g of sodium a day.
If that doesn't help try adding back some carbs.
Seaweed sounds like a good idea. It has lots of iodine. I supplement with iodine and I feel loads better on it.