Sorry to hear that you had all those tests and they cannot find out why. High stress does cause issues to the body and it can manifest physically in different ways as per the individual and how they handle the stress. Glad you eat fresh foods and coconut milk which is high in saturated fat and calories. That would help you gain weight.
I know it's a symptom of an underlining cause, one in which all the doctors I and test have failed to find. No cardiac issues, had tests, no seizure problems, had tests, no brain problems, had MRI, no blood issues, had all blood tests that can be done 3 times, no thyroid problems, had that tested...all in all 3 doctors 3 ent's and a couple of shrinks find NOTHING except hearing loss in the upper frequencies. So they said eat a low sodium diet. No Milk cannot drink milk as it seems to trigger ringing so I drink Coconut milk. No ice cream or dairy as it also triggers noise, already eating fresh foods and not eating out, so must just be stress..huh?
Tinnitus is a symptom from an underlying issue. Low sodium diet is not one of the recommended treatments for this; however, if one of the underlying issues is blood vessel or cardiac disease, then low sodium is appropriate for treatment. If you avoid adding additional salt to your food at meals that would help you cut 1/2 to 1/3 of your sodium content a day. Add additional spices such as pepper, garlic (not garlic salt), lemon, and onion to name a few. Sodium content is high in all our convenience and prepackaged foods, cold cuts, smoked meats (smoked ham, bacon, etc), canned foods (soups, stews, vegetables, etc), and cheeses. There are products out there that are made low sodium, so you need to read the food labels. Suggest eating mostly fresh foods and home-cooked meals (lower in sodium then convenience foods and restaurants). Are you able to drink milk? If so suggest milk-shakes (low fat if you have a cardiac issue) at all meals for additional calories for weight gain. A fluctuation of 5lbs a day is normal if you are doing physical work. Sounds like you have something going on if you have lost weight and having digestive problems as you stated. Suggest you get that checked. Hoped this helped you.