I would predict a few outcomes. If you actually did this, ...
First, 3 glasses of tea daily will have a diuretic effect. Long-term, you could stress your kidneys and develop prostate or kidney infections. The latter effect depends on the strength of the brew and whether the tea was a more common blended black and orange pekoe or something more varietal, like the lapsang souchong or oolong variety. Your sleep habits might be severely disrupted because tea DOES contain caffeine, which is one of the alkaloid poisons. As such, in extreme cases, it could negatively affect heart rhythms. I would anticipate atrial fibrillation or A-fib, one of the more common heart arrythmias.
Second, a total of 36 packets of sugar per day would lead to - at the least - insulin resistance and weight gain. That could easily escalate to metabolic syndrome, which is a precursor to type II diabetes. If the weight gan is not controlled, you might also see increases in blood pressure. You would also probably very strongly increase the likelihood of dental caries (weakening/loss of tooth enamel) leading to the need for fillings or more severe dental work, because sugar in the mouth promotes growth of bacteria that are not your friends. Finally, you might develop a breath like that of a buzzard. Those unfriendly bacteria emit noxious gases, so folks would smell bacteria farts on your breath.
