You might be smoking your manly "vape" pen more maybe? Or it doesn't seem like it, but you are? Without that smoke sensation and carbon monoxide, I think we take more nicotine to compensate. Or at least that's how it seems with the gums. And who knows how they normalize concentrations, equivalent to a UltraLite or no-filter PallMall? What if that Marlboro just sits at the side of your mouth most of the time?
Seems like the carrier fluid is usually propylene glycol and glycerol, which can both give you the shits, but not in those amounts.