Once I really got into the swing of vaping, and some good gear in hand, I found that I had some physical reactions to being able to get more nic in my system than it could handle.
I had to learn how at a: stay properly hydrated, b: eat balanced meals, c: control my nicotine curve. Sleeplessness (from vaping too high mg nic later in the day) vomiting (yeah that 36 mg nic was an overdose in my spang new happy fun Nautilus tank that made all the flavors totally pop like crazy ((don't find this out in your car on the road, mmk)) ), blood sugar swings because flavors are NOT a substitute for eating...
You really can hurt yourself having too much fun, but experience will help bring on moderation without inhibiting a full and happy vape lifestyle. That being said, you can help yourself by living a balanced lifestyle while vaping. It is within your grasp to take control of what you are having fun with, vape on, and stay calm. Don't let panic stress you out if something unusual happens with your body; pay attention to it, back off a bit on the chain vaping, and motor on.
Lower nic levels in the evening, (I got some 3 mg nic so I could blast away and enjoy and still sleep, when I had trouble with sleeping from Too Much Fun, and it helped a lot). If you have the runs, get you some cheesen tortillas, and quesedilla a bit to help while you are getting your balance with vaping.
A week into vaping, your body is just starting in on the changes of giving up smoking. Carcinogens are not all you have taken away from it's daily routine; all the additives in cigarettes also have withdrawal related effects on the system. Sinus drainage as your breathing reverts to normal function will end up in your stomach and effect your digestion. Hang in there!!! You can do this, whether you keep vaping in perpetuity or not. Coming out the other side from all the side effects of NOT smoking is like walking into a whole nother world you didn't remember existed, and you will really love what it hands you back, of life and enjoying life.
