My body begun to respnd for stimulants

Since after my 7 months of rebooting I have noticed and begun to sense lots of changes to my body.
When I was fapping, my body had already stopped to respond for any stimulants, such as tea, coffee, even for Khat (Local stimulant leaf which has a stimulation dose more than 15 cups of Coffee). But now what happened?
With 1 or 2 cups of coffee, I could successfully read books the whole night or do Job, with no sleep no rest. This never happened during my fapping years. What I understood is that my brain and body have begun to regain back its innate sensitivity. Any Idea encouraged, what do you think?