yeah you have to budget your time the same way you budget money.
also try to set aside specific areas for hobby activity and dont mix it with other activities. like, dont game on your school/work computer, and dont do work on your gaming computer. these makes it a lot easier to keep discipline.
a physical hobby is good for you too. I tend to get sucked into gaming a lot during the winter when its too cold outside for other things, but I have outside hobbies for the rest of the year.
big thing to remember is that gaming is just another form of escapism. for some people its liquor by the gallon, for others its reading books everyday, for others its gaming. a counselor I knew used to say that if drinking leads to problems in real life, like making you late for work, or whatever, then you have a drinking problem--same is true for any kind of escapism..