I believe that this matter has to do with your skills as a magic practitioner. I believe the best answer for your question is to practice.
I also second what Dillon said.
Ungrounded power means that you may be an inexperienced meditator, you may be inexperienced when working with your personal energy, and sometimes what happens is a newbie will have a lot of energy flowing through them, emotional energy, spiritual energy, etc., and instead of having this energy ground into the Earth or project into the Universe, the person's body will kind of shut down, like a short circuit, and they'll fall asleep.
This is usually very harmless and is just your body's wisdom taking control. By practicing meditation and basic energy techniques you can avoid this.
Anyway as I said practicing is the answer. Learn about various meditation and energy techniques.