I've noticed that my penis size seems to have shrunk from 6 inches to about 5 inches, and I'm really concerned. I've gained around 7 kgs recently, and I also drink a few times a week. I quit smoking regularly about two months ago but used to smoke a lot before. Could these changes be affecting my size and stamina? What kind of diet or lifestyle changes should I consider to maybe get back to my original size and boost my stamina?