Am I dehydrated or what?

Very dehydrated, when you stop sweating you have reached the point of heat exhaustion. Which includes all they symptoms you describe,light headed, dull ache, small headaches. Just drinking water will not help, you need gatorade or power ade or something like that to restore the lost salts and electrolytes. Try to not drink to much caffeine or power drinks which often have stuff like kava kava in them, those sorts of things will make you more dehydrated The dry cough had nothing to do with. Give your self a day inside, drinking lots of fluids, lemonade is good. where it's cool, you'll recover from it quicker.