A good recipe is 1/2 tsp "no salt" and 1/2 tsp sea salt, 1/2 tsp of baking soday, lemon juice and stevia for taste. This is basically the cheapest recipe of electolite balanced drink. It tastes discusting so just chug it or have sips throughout the day would be better.
It sounds like you are depleting yourself of sodium. sodium is in almost every processed foods as well as natural foods like celery, carrots etc. But, sodium is one of the fuels for our energy. You ever notice how sweat tastes like salt? Well it is because during your race you are sweating out all the salt, so to speak. Most people neet more pottassium as it is the the better half of sodium that balances out our body's water retention. But after a race you need salt or sodium. Look at food labels and you will quickly learn there is sodium in almost everything. If you find your body craving burgers, chips, cookies etc it is because the body desperately needs sodium (salt).
I don't know your current diet regement, but I hope this helps
Jen