Here's a concept that far too many people don't seem to understand. You get every nutrient the body needs to function properly from food - with one exception: water.
Although you do get *some* water from food, it isn't nearly enough. The body loses around 2 quarts of water per day through its normal functions - breathing, kidney function, temperature regulation, and waste disposal. This water *HAS* to be replaced. Most people don't.
The medical profession has conned people into believing that "fluids" and water are the same thing - they're not. Fluids have a diuretic effect that forces water out of the body. The body was designed to use water, and there are no substitutes. And the only way to get the water you need is to drink it.
But the main thing that people don't realize is that every function in the body is tied to water - water regulates ALL of the body's functions, and when you're dehydrated, it affects those functions. This is why water is the most important nutrient the body needs to live - and it's why most of the body (75%) is composed of water.
Your symptoms don't sound like a clogged artery, per se, although you might have this problem as well. The dizziness indicates orthostatic hypertension - low blood pressure. And because blood is 94% water, it signifies low water levels. The dizziness comes from a lack of oxygen (carried in the blood) from getting to the brain. This usually happens when a person stands up too quickly, but it can happen any time an area of the body needs water and it isn't available, so it gets borrowed from somewhere else - and the brain is ultimately affected.
Insufficient water is also connected to the other issues you mention. You might try increasing your water intake and abstain from other beverages for a while and see if this helps. Whenever the body starts acting abnormal, the first thing a person should always try is drinking water to see if that does any good.