There are not really 'treatment centers' for online addiction, except for when there is a sexual component---- in such cases there are a couple well-known places, such as 'the meadows' in Arizona (I think that is the name). You have insight into the problem; the piece missing is the motivation to change. Realize that many people will be stuck in a condition of fantasizing about how things 'could be'; they almost have a fantasy that things will somehow just change, without their having to make sacrifices or work at it.
If you have identified an area where you would like to change, recognize that there is always AMBIVALENCE about the change. Changing will always mean giving up something that you like, or that is comfortable, or that has a 'good side' to it. Recognize that ambivalence and put it in the light of day; see it for what it is. Look at the thoughts about NOT changing-- how it is less frightening to stay the same, how change will mean being self-conscious, anxious, and uncomfortable... but recognize that all of these will be only TEMPORARY, and that eventually the new behavior will become much easier.
And then, just decide to change. If you do decide to change, you need to place firm boundaries that you NEVER cross. You never go on the internet before 8 PM or after 10 PM-- ever. Realize that if you cross a boundary, even if you intend to do it 'just once', the boundary will cease to exist. If you decide to exercise every day, you can never miss a day-- not until the pattern is set and routine. Etc, etc...
Change is always hard. People come to me and say they really want to change... and then they fight me every step of the way. That's just how we humans are...
Online gaming can absolutely become an addiction. Addictions like these are called "process addictions". Whether you are addicted or not is something for you and profession to discuss. Hopefully the doctor can give you some good advice on where to go from here.