How to change my aggressive ways? (emotional help)

I am aggressive and easily irritated. Some may think I am bi-polar. I am constantly getting irritated for small matters and then become aggressive with the people around me for an undetermined amount of time. I need to change this because of the way I am with my girlfriend- She seriously has a lot of patience with me, and I recognize that because of this way that I am, i might lose her. How do I go about changing myself?

I believe this aggressive state is because of various reasons. This would include heavy stress on maaany problems that constantly appear, which to name a few: my hatred against a family member of mine and how I compete against him(even though he is 7 years older than me) my tmj problem, my teeth problems (wearing braces for 6 years and still not ready), my needing to find a job or else I wont have a place to live problem, etc.
Oh, and this heavy, subconscious, importance that I give to money- my goal is to make a lot of money. I can`t simply tell myself to stop thinking this way; my mind simply doesn’t stop thinking about how to make money.

Back on topic- I just finished a conversation on the phone with my girlfriend and I noticed I was already becoming aggressive with her! She ended the conversation as fast as she could so she could turn off the phone.

Help! How do I change my life?