One thing I've noticed, is that both quitting nicotine RAPIDLY, and overdosing myself, have so many similar effects, that I often go through periods where-in I think I am getting too much nicotine, but I am in fact not getting enough. I also go through periods where I think I am not getting enough, and I am in fact overdosing.
The effects of nicotine overdose, throughout a day for example, for me, are a laziness, a severe mental malaise that bolsters an unwillingness or, a lesser probability that I will think deeply into something. Overdose can also involve emotional blunting, a steady feeling of unease/anxiety, switching to warm euphoria for short periods, then back to unease. Light overdose can also include extreme euphoric warmth, akin to stimulation from other drugs and/or natural stimulation of the dopaminergic centers, such as sexual arousal. Extreme overdose, where-in I had chewed two 4mg pieces of gum, or had chain vaped for 30 minutes straight, or had smoked 2 cigarettes in a row, also include light-headedness, headache, heart palpitations or abnormal heartbeat, yawning, eye tearing, and fatigue. Important to note that these are symptoms that all appear when I am having a panic attack due to, for example, abstaining from nicotine for an evening, sleep, and a morning.
The effects of nicotine under-dose, throughout a day for example, for me, are extremely similar to the above paragraph addressing overdose, however, I think with under-dose, I am yawning regularly, my eyes are tearing up, physical energy is wiped, more likely to fall into rapid escalations of anxious self consciousness. If I am not vaping or smoking, and I am at home alone, I am completely wiped. Looking back, it can almost be described as another world. I am zombie-like when I haven't gotten a significant hit of nicotine in a day or day and a half. I feel as if I need to get up and move when I am trying to study something or read. I seek out things like social media walls, likes/reactions. Bites of food.
Interestingly though, I have quit nicotine in the past completely, by essentially replacing nicotine with exercise, and also using exercise as an anti-depressant and anti-anxiety drug. I remember running to my weight bench each time I felt an anxiety attack brewing my chest. I remember starting every day with jumping jax. I remember prior to attempting the quit, I had reduced my use of nicotine to once every hour on the hour, and during my quit, I simply replaced the nicotine with the treadmill or the weight bench. 4 o' clock, running. 5 o' clock, running. 5:30 anxiety attack, running. 6 o' clock, running.
It sounds extreme, but to date, that was the only time I have ever made it to completely nicotine free in my entire life, since age 14.