Buddy, your just 1 year older than me and you have a son. You must be feeling stressful at times because being 19 and having to hold a great responsibility of a child can be pretty tough sometimes.
About the girl you've just got to give her up, completely. And by giving her up completely means letting her go free and not being destructive and possessive of her. By letting her go, you aren't just only letting her free, you are actually also giving yourself the key to peace and freedom. Only when you are at peace, will you enjoy and live life.
What your son needs are not presents or money. He needs your care and concern, your love and affection. Kids need to grow up with showers of love and they need to know that someone is always behind their backs. (their fathers)
If Runescape is draining your resources, you have to quit it. It may have gone through the thick and thin with you, but now you have bigger responsibilities to uphold. You had $117 in your bank and spent $100 on Runescape, that is not very wise is it? You spent over 80% of your savings on RSGP when you need the money for the future, for you and your son.
Like you said, you are addicted to video games and realising it is a great start. Many addicts do not realise and fall into denial when confronted with the truth. Since you understand that you are suffering from a video game addiction, take action. Help yourself through this, go cold-turkey. Enlist some self-discipline.
Your life is going some ups and downs right now, like a roller coaster ride. You can try take control of the ride, and although you cannot completely control the entire ride, you can control how you react to it.
Set rules, set goals, set disciplines for yourself to follow. It could be as simple as save $50/week, exercise 3 times a week or spend at least 2 hours with my boy a day. These small goals and disciplines, if followed, will give you a sense of control in your life which is vital.
If you have failed 3 times, then try harder. You can't apply for the same job the same way if you have failed the first time. You aren't getting it if they don't think you are qualified.
Try other jobs in the meantime, it's good to chase what you want. But at this crucial point, take what is available, but that does not mean you stop trying. You can keep trying, keep applying, but you have to prove to them you are the right man for the job.
Your son needs you, he needs a father and a conducive environment to grow up in. Get rid of your bad habits and addictions for your son, and most importantly, for yourself.
Buddy, go go go!!! I want you to come back with a list of goals & disciplines . Perhaps make a blog to follow your progress and keep you motivated. You can try blogspot or wordpress, whatever suits you. You can do it, faith in you man.