It really doesn't matter what the culprit is. All those things need to be addressed anyhow. Even age.
As I get older I find that I'm not the invincible person I used to be. So I changed some eating, exercise and other habits I felt were not helping me.
Probably a lot of heat where you are at. That'll sap the energy out of anyone.
But for certain, be talking to a doctor. Let them know all your concerns. Don't make them guess what is bothering you like my wife used to do when she went to the doctor.