Here are some of the effects of acetaldehyde (significantly more toxic than ethanol):
•Is responsible for most of the symptoms of a hangover. Causes dilation of blood vessels in the brain which result in the characteristic severe headaches.
•Attacks and forms complexes with many proteins and nucleic acid (as in DNA and RNA) disrupting their normal functions.
•Blocks secretion of proteins by the liver and causes swelling of hepatocytes (liver cells).
•Binds and inactivates glutathione - the body's main antioxidant - thus increasing oxidative stress and allowing free radicals to damage cells throughout the body. Mitochondria, the energy producing machinery within each cell, are particularly susceptible to free radical damage.
•Impairs the function of lymphocytes (an important type of white blood cell) and red blood cells (those that transport oxygen).
•Increases the release of adrenaline causes heart palpitations, anxiety etc.
The last one makes perfect sense. What I described it to people as was that it felt like my body was releasing adrenaline that just about a month ago I had it so bad that I was jumping out of bed and having to pull over on while driving because I thought I was dying.