I had heard that there is a lot of Serotonin produced in the portion of the stomach that is removed in producing the sleeve. I regularly had issues with being lethargic and feeling depressed off and on throughout the first year. No lab work was conclusive, low but WNL. I took liquid geritol and increased my D3 intake during that time and just kept plugging away. I am 19 months out and still working at it every day. I've lost 136 pounds and have 15 to go. Sometimes the emotional journey is the greatest hurdle that we face. You'll get there and it will ALL be worth it!!!