It is common to have difficulty sleeping for a while, because when you practice Qigong, your mind is energized and your spirit raised. This keeps you from falling asleep. Pay attention to your breathing, thinking every time you exhale that your body is becoming more and more relaxed. Inhale longer than you exhale to make the body more Yin. Don’t use Yi to lead Qi, but just breathe and relax, and soon you will fall asleep. You may also practice Embryonic Breathing, leading excited Qi down from your head to the Real Lower Dan Tian. Then the mind becomes calm and the body relaxes.