1. Guesstimate your sodium losses. Weigh yourself before/after training. Look for salty taste, residues of your sweat. For the OCD: Get your sweat measured, sodium content ranges from 200 to 2000mg/l. Track your sodium intake for a couple of days.
2. Eat accordingly.
3. Worry about too much salt if you have high blood pressure, eat a lot of salty, processed foods (bacon, cheese, pickled/salt-dried fish, salty soups...) and dont sweat much.