How do I tell my mom I don't want her here and I need a break from her?

Since it is her home you have no right to ask her to go anywhere. She is only messing up your and your son's lives because you allow it by staying with her. You need to get a job, apply for state day care and apply for public housing. A homeless shelter is one option for you and your son if you can no longer stand living with your mom. They can help you find a place to live and often you get into public housing quicker if you are staying in a shelter. They won't tell you this, but I worked with Social Services for 30 years and had a number of client's who were in homeless shelters that were placed in public housing fairly quickly.