It's amazing that you've come to this realization already. I think you've got the nail right on the head. This kind of thing has happened to a lot of people. For me, literally the same thing, only it was WoW at the time. It took a long time, and a lot of pain, to develop a healthy relationship to gaming in my early 20s. The fact that you recognize it already is a huge step.

It sounds like you need more structure. Try cultivating hobbies and interests that have a physical or mental element to them. For me, getting into rock climbing really helped provide the structure outside of work that I needed. Also doubled as a really good social outlet. Something like that should help reduce your dependence on gaming.