I can't say because everyone is very different, different metabolisms affect how long people go through withdrawals, among other factors. Have you read about PAWS? post-acute withdrawal syndrome - this is when you have lingering withdrawal symptoms for months after discontinuing a drug. Lethargy can be involved, but a lot of it is psychological stuff like depression and anxiety and what not. It's hard to say exactly how long it will last, but after 26 days, amphetamines are long gone, but your dopamine levels might still be screwed up. Even if it does take months, it will only get better. I highly doubt you'll still feel this way even in a couple weeks... I know for myself part of the adderall withdrawal was psychological in that I was so used to LOVING to clean and study, for example, because I was smashed and extremely euphoric so it was exciting to organize. Naturally, it's not SUPPOSED to be an intense, euphoric experience to study and have your brain flooded with dopamine... but I was so used to that that going back to doing normal stuff in my natural state seemed terribly boring, empty, depressing.. I felt like I didn't have the energy to do anything. What helped with that for me was sort of mind over matter... I kept reminding myself that sweeping is not supposed to be an ecstatic experience, life is boring sometimes, and just to force myself to do what I needed to do and try to think optimistically. It really does help, and after about 6 weeks I'd say I was used to doing things that require energy without being extremely amped for them.