One of the symptoms of nicotine withdrawal is difficulty concentrating.
For the first few days, you will have difficulty concentrating. Usually, we associate being able to concentrate with lighting up. It takes a little while to adjust. The void and craving distract you, which makes you feel like not able to concentrate.
In my experience, it only lasts 2 to 3 days, where your head feels like an empty coconut. It feels like it’s all empty, and nothing is there. It’s a weird feeling. The mind is trying to adjust to the body sensation that gets triggered due to the void of nicotine in the bloodstream.
Please note that this is short term problem, and there is only to gain after this hurdle. Think about the long term. After few days, all of this will clear, and you will enjoy a full life without any addiction.
From Chain-Smoker to Non-Smoker 