Why does alcohol make you sick if you have too much? Is it nature saying..

Because having too much of anything, especially in the relatively short time in which people consume alcohol (several bottles over one or more hours), will make you throw up

In addition to it agitating the stomach it goes into the blood and bonds with certain cells and dehydrates you so

Either the liver can't handle it or an allergy perhaps.

Alcohol is essentially treated as a toxin by your body to be broken down by your liver and kidneys.

Hydrate, you loon