How long does it take someone who quits opioids to start feeling normal again?

Up to a few months: There is a large difference in response that's individual. Some people don't feel a difference when they quit, and others feel lousy for months. The brain likes having opioids around and would rather have you provide them (pills) than making the brain make them (endorphins). Our bodies preserve energy whenever it can get away with it. It takes a lot less energy to make you get the pills.