Oh, great. Now vaping causes flu! Somebody tell Gottleib - it's an epidemic!
Just kidding, of course. You probably have the flu. Or, you're experiencing withdrawal, and your body is more sensitive to it than some. Dude, first few days are pretty tough. And withdrawal is real, but the physical part of it is short lived (psychological part can last a long time). I don't know if you've quit before, but even if you're still getting nicotine, you're kind of addicted to getting 7,000 chemicals from tobacco combustion in your body. Naturally, if you feel that bad, see a doctor. But trust me and others who've smoked 40+ years - you're not gonna feel quite right the first few days. But see a doctor anyway, if only for piece of mind. Trust me again - vaping will make you feel MUCH better than smoking, eventually! Oh, and if your doctor suggests you quit vaping because it's dangerous, and go back to smoking, switch doctors immediately.