Our lovely Emjay posted this a while ago, it might just help you to understand what your body is going through
When you stop smoking, you will most likely encounter one or more of the symptoms associated with "quitter's flu." All this means is that your body is having trouble dealing with the sudden withdrawal of nicotine from its system. The symptoms, which are similar to a cold, are only temporary, but may last longer in some people than in others. Most people who quit smoking will only experience "quitter's flu" for a short time. Some symptoms include: cravings, irritability, trouble sleeping, fatigue, stomach issues, stuffy nose, sore throat, headache, and chest tightness.
Fighting Negative Effects
Techniques to fight negative symptoms vary, but one is to drink lots of water. It's important to stay hydrated during this time. Another tip to fight cravings is to wait it out, since most cravings don't last past five minutes. Many daily activities such as drinking, eating or stress at work can trigger cravings--acknowledge why you may be feeling the craving and try to change your mental state or thought process at that time until the feeling passes. Other tips are as simple as deep breathing for relaxation or discussing difficulties with others so that you don't feel alone in your struggle to quit.
Short Term Positive Effects
There are many positive effects to quitting smoking. Some occur almost immediately, some over time. Within a period of only 20 minutes, your blood pressure will return to normal. In the first 72 hours, your carbon monoxide level (which is poisonous to our bodies) will drop to half and oxygen levels will return to normal. Sense of taste and smell will return along with a decreased chance for heart problems. Energy levels will increase and breathing will become easier.
Long Term Positive Effects
Over the next year, circulation will increase, coughs and wheezing should subside, and risk of heart attack will drop by half. In the next fifteen years, stroke chances return to levels of a non-smoker, as well as risk of lung cancer and heart attack.