I'm surprised it had that kind of effect..

Did they explain what symptoms it was for, any other remedies given? In the past (many years ago) when I took my sons , they always gave a few remedies.
Theirs was for allergies & food sensitivities.

Did they explain how to take it?
I'm assuming it is the very small pellets that you place under the tongue?

Usually the dosage is x amount of pellets many times a day.

Taken approx 30 minutes before or after any food or drink. Anything other than water will affect absorption..

Helpful Guidelines for taking Homeopathic Remedies
http://www.homeoint.org/site/price/guidelines.htm

info on Nux V-
http://www.abchomeopathy.com/r.php/Nux-v