I hope you're feeling better by now.

Short answer: no, these are placebos. There's no solid evidence that large doses of vitamin c provide meaningful health benefits. Your body can't handle a "mega dose" of vitamin C and your kidneys filter most of it out so you urinate most of it out anyway. With supplements in general, it's best to get nutrition from a healthy and balanced diet anyway -- the nutrients are far more bioavailable.

The history of how "alternative" (read: fake) medicine came to latch on to ascorbic acid as a cure-all is interesting though. Linus Pauling famous for his work in subatomic physics, but he later went far afield into medicine, an area he was much less adept at, and developed a pet conjecture that vitamin C had extraordinary health benefits. He wouldn't let go of his pet conjecture even in the face of experiments to the contrary. Quacks latched on to this idea using the terrible reasoning or "how could someone so smart be wrong?"

https://skeptoid.com/episodes/4103

Experts need to have the humility to understand that expertise in one field does not transfer to another field. This is such a common problem in STEM