What can i do if my online game addiction ruins my life, how to start therapy without professional help?

Professional is best: Get with your personal physician and into the evidence-based mental health care service community. If this is gambling, there is gambler's anonymous. Some compulsions may respond quickly to medication but you'll want a competent therapist for evaluation and guidance. The prices can be scaled -- and this is your life, so be prepared to do what you must. Best wishes.