Its really sad May Allah(swt) help you.
I know its obvious when a person becomes addicted to something then its hard to leave that habit easily. But its not impossible. The only thing required is a firm determination. When we get sick and the doctor advises that we have to leave few things that is necessary for our body, though its not a easy task but we all try slowly to leave that thing to keep healthy. Any sin( Gunah ), the major effects it causes on us is that it takes the ability of thinking from us. But Allah (swt) has given us Aql ( intellect) and also has said if we try in His way one step He will come towards us 10 steps but its you and we who has to take initiative and start it. It takes time to keep aside any addiction but for that you have to do few important things and the very important step in this way is that:
1- You have make your decesion firm and seek help from Allah.
2- If possible for you and your are doing any any important job by using internet please stop using net data for few days.
3- Dont go in privacy and always try to be with your family members
4- Make a vow (ahad) that anytime you commit this sin will give few money as sadaqa to the poor. If it works then ok otherwise make your vow bit harder and do niyyat that you will fast one day for each time if you repeat the same sin.
4- Always be with wuzu and recite dua in any language which you know.
5- Dont eat full stomach. Stop eating while you are still hungry.
6- Dont go to the bed unless you feel sleepy.
7- Dont be alone.
Ask Allah to help you as much as you can inshallah He is the best helper and likes to help who seeks His help.