You are suffering from opiod
dependence and it has very strong withdrawal symptoms
which you are experiencing . It is good you have motivation for quitting , as it very important in de- addiction.
Now all you have to do is , to see a nearby psychiatrist
. He will prescribe you medication which will make withdrawal phase easy and will give you long term management also
It is better if you involve your friend or family member in your treatment, as it help in relapse prevention