@the-MOUSE
I doubt you have too much stomach acid.
How could you have too much when your condition of being both low in CO2 and NaCl disposes you towards making less rather than too much stomach acid, being that your condition of metabolic acidosis deprives you of hydronium ions (being hydronium ions in blood would be transferred to the cell in exchange for the potassium ions inside cells, which explains why you are high in serum potassium - as that is how the body adapts to metabolic acidosis by trying to make the blood more alkaline with potassium ions brought in to blood by that exchange between hydronium and potassium ions.
You are also short on salt (as well as sodium and chloride) that you are low on chloride needed to make hydrochloric acid aka stomach acid.
Because you are low in CO2, your platelets cannot carry serotonin into your lungs, as CO2 is needed to enable platelets to carry serotonin to the lungs. It is in the lungs where most of your serotonin is deactivated. If serotonin is not being deactivated in your lungs nor carried by platelets, you have plenty of free serotonin which would end up also in your brain.
Taking cyproheptadine hasn't worked for me when I was having problems with my lungs when I had bronchitis. I couldn't sleep for days on end and I think the problem was simply too much serotonin messing my brain.