What Causes Syncope, Body Heat, Speech Slurring, Hands Numbness And Nausea?

I feel faint and get hot all over and my speech becomes slurred and i feel numbness around my hands and its hard to use my fingers afterwards. i than feel naseaus and headachy. I have been experiencing this for 3 years now and have been tested for diabetes and other blood work. both normal. i dont know what to do.