Common withdrawal symptoms include anxiety, irritability, frustration, anger, difficulty concentrating, insomnia, and restlessness. Think of them as positives, signs that your body is recovering. They can begin as early as the day you quit and significantly improve over several weeks. Additionally, you may experience cravings for cigarettes. Not everyone has withdrawal symptoms, but if you have a history of experiencing or even relapsing over them, you may want to try a quit smoking medication to make withdrawal more manageable.
Some withdrawal symptoms may be exacerbated by caffeine, especially anxiety and insomnia. Cut your caffeine intake in half to see if it helps. Also, try to stay active, eat well and get plenty of rest.