everything above is great information, another thing is what AF flavor are u smoking? because some flavors just make people sick and if it is dyed it can make you sick from smoking the dye, so try smoking a flavor without a dye and see if that helps. Other than that make sure the shisha isnt burning make sure u drink a lot and eat before or during your smoke, take slow hits and space them its supposed to be relaxing
other than that make sure the coals are completely ashed over usually with quicklights once they fully light themselves wait about 5 minutes before u start to smoke. Hope this helps!