This sounds like an energy problem, as Anemos Aiteros suggested, or also a malnutrition problem like Seguace di Satanas suggested. Probably both.
In my experience, Magnesium supplement is highly needed to help reduce physical fatigue. In a demanding moment, I supplemented daily for a couple of months and I noticed I felt much better.
As far as I know (also by direct experience), Magnesium is highly needed because it is an alkaline mineral, the body uses to contrast acidity. Body acidity results from high stress (and stress hormones high levels in blood), excess of acid-causing foods (white sugar, yeast, alcohol) and lack of alkalizing vegetables, fruit and so on, smoke, pollution and long-term stressful lifestyle. I do not know the medical causes but I observed all of this on myself, and corrected. High levels of Magnesium were needed for a while.
So if your body tends to be acid, lack of Magnesium may occur, so fatigue comes in. Vitamins too (B vitamins mainly) may be needed for physical energy production.
Regarding the fact you feel down when going out, if you are weakened at the moment, external pressure from mass mind in densely populated areas may be a challenge, it increased after Covid - it depends where you live. Aura of protection and strong 2nd and 3rd chakra are very important.