Mood Swings

I was happy all day until now.  I am so stress and depress to the point I want to hurt myself.  I am tired of the mood swings. One minute I am happy and the next minute I am sad.  It is too many ups and downs for me.  I don't know how to handle this.  I tried to do something I love but it is not helping. I only get more stress. I got a part-time job. I wonder did I made a mistake of getting a job prematurely but I need something to do.