I've done ecstasy plenty of times and never experienced anything that I would describe as "losing my mind". Just waves of euphoria and a sense of eternal bliss. Also a deep understanding of what it means to be alive, and some double vision.
Taking a supplement with magnesium is said to help relieve jaw tension, methods mentioned by Bonger also work.

Day after has never been a problem for me, especially not the first times. With more frequent use I have experienced bouts of light headedness the days following, especially when rising quickly. Take a vitamin and try to get some sleep and chances are you wont feel some bad. Especially not after you smoke a few bowls.