Starting a New Job and Controlling My Emotions

I start a job tomorrow at a retail store and I think I'll finally keep this one. they have me doing stocking so that's great for me because less human interaction. I never kept a job more then 2 weeks because anything rude someone says to me, I don't hold back and I'll lash out. and if I also don't like the job or I start feeling any hint of anxiety, I'll walk out . I just got a good feeling for once about this job. I have to grow up. I'm 30 years old and still haven't got controlling my emotions down and I have to know that I won't like every job I have but I need to have a job in order to survive and have my own so no man can feel the need to control me because he pays for everything. I want to be my own boss