Cut back on the vitamin c. Too much vitamin c does cause diarrhea.

"tired,heavy,lightheaded,dizzy when I stand up,I woke up today looking deathly white,and had diarrhoea "

That is probably from dehydration and potassium and sodium depletion due to the diarrhea. If you drink some milk, eat some yogurt , or eat some vegetables and drink enough water that will probably help quite a bit. Also eat some salty foods. You should start taking vitamin c again, but in more normal amounts(perhaps no more than a gram or two a day?)