Doubt it...
I seriously doubt if you're sick from high cortisol levels.
Cortisol levels are elevated transiently during stressful situations, but if the stress is chronic (i.e. combat zone), your body actually adapts to that in a matter of weeks. One of the few times there are chronically elevated cortisol levels is in Cushing's Syndrome or Cushing's disease.
If you think you have this, then you'll be tested using something called a dexamethasone challenge test.
More likely culprits for being sick are exposure to bacteria and viruses, overtraining, and comprimised immunity form long AAS cycles (thought this is rare, and probably not the issue).
Phosphatidylserine will mostly be destroyed by First Pass metabolism in the gut and liver, and won't have any measurable impact on cortisol. Not overtraining would be a better option.
These "high cortisol" claims are the same things that bogus junk like CortiSlim advertizes as the reason people are fat, and can't lose weight when they're over 30. THe reason people don't lose weight is the same as it always was: lack of exercise, and shitty diets.