A big x2 on this one!!! except I don't take the chewables. I've taken 500 or 1000 mg of Vitamin C with supper every night for at least 8 years and -- knockin on wood -- have NOT had a cold or been sick in that entire time frame.
Though it won't help that much for the crap you have right now Inkie (maybe help you kick it faster), it will save you from getting sick next time.
Vitamin C is something you really can't "OD" on so to speak since your body can't retain it like some other vitamins. If you don't eat a lot of fruit or drink a lot of juice, take Vitamin Cs instead.
Best of luck with the remedies and hoping you feel better soon!!! :-D