I have been lightheaded as well, when I stand up. I don't know why. Maybe someone will be able to explain.
How much celery are you eating? There are only about 100mg of sodium in 2 stalks of celery. Maybe if you increase your celery intake to equal the amount of sodium you are getting from seaweed or sea salt, you can get some of the same healing effects.
I don't have anything specific to recommend, so I hope others continue to chime in.
Noting Josh's input here, though:
I would give more calories a try though. Depending on the size of your dates, you might be well under our baseline of 2500 cals per day for ladies. If they agree with you, add in some nans or plantains. Especially in bulk, they are some of the best price performance fruits you can find.
The best way to tell if your water intake is sufficient is if you are weeing at least 8-10x daily, a clear lemonade color.
Also, while it might be preaching to the choir, as it sounds like you're already recognizing the problems inherent in salt, this still might interest you:
Common symptom of under eating is dizzy upon standing.
Another thing can be lack of activity. Body has become sedentary and therefore circulation is weak.
You got a few things here. Hard to guess but I would say undereating and lack of activity. I assume your going to bed early consistently.
How many carb grams is this per day? It doesn't seem like enough. I'm sorry I don't have time to enter it all into cronometer for you right now to see.
if i had to guess i'd say youre eating like 1,500 calories, which would be why youre lightheaded. count your calories to make sure youre getting at least 2,000 unless you enjoy the dizzy lightheaded feeling of starvation.