Taking too much CBD might cause drowsiness. People often fall asleep earlier than usual and stay asleep for several hours when this happens. Some people even find that too much CBD will leave them feeling groggy the following morning. In very rare cases, taking too much CBD might drop your blood pressure, which could result in dizziness and Lightheadedness. Other people find they get nauseous when they take too much CBD. If you experience any of these symptoms, remain calm and wait out the effects. The next time, reduce the dose of CBD to avoid these adverse side effects from happening again.