giraffes, re the labyrinthitis - this is a common precursor for ME, I don't know if that helps you or not.
Depending on how often you get it, and how long it lasts, it might not be viral at all though - I had transient vertigo for ages, plus 2 bouts of labyrinthitis, and the vertigo was cured by my osteopath putting my neck back together the way it should be. It might be worth seeing one for that at least.
The vitamin C is to replenish your immune system, which requires vit C, zinc and selenium to function - you sound like your immune system is running on empty and needs an urgent boost.
One thign I am sure of - you are not lazy. You probably weren't depressed before and if you are now it is a reaction to your illness, not a cause. Please don't fall into the medics trap of "we don't know what's wrong with you, if anything, so go away and pull yourself together".
Self blame will not make you better.