Dizzy, tired, and headache after a tooth numb at the dentist. when will this go away?

Common for this: This can happen because of the stress of the dental appointment, the novacaine, and keeping your mouth open for a long time. Take whatever otc pain medication that is safe for you, such as advil (ibuprofen). Make sure you are not dehydrated and you have eaten, even if only soft foods. You should feel back to normal by the morning. But if you don't then call the dentist.

Can't determine: As we are unaware of your medical history, medications you might be taking, and can't personally examine you, there is no way to properly answer that question. If all those symptoms are related to your recent dental visit and treatment, they should subside shortly. I suggest that you call your treating dentist and ask him\her that question.