How do i get my mom to let me do things on my own?

I'm 19 years old. My mother doesn't let me get a job or go outside on my own. It's been like this for about a year and a half now and it's driving me mad. If I try to go anywhere on my own, she follows me, and refuses to go away. If I ask her if I can get a job, she says no. Today I tried to go on a bike ride, and she stood in front of me with the front wheel in-between her legs so I couldn't go forward, all because she didn't want to ride and she wanted to come with me. How do I stop this? I'm getting desperate. I've started to lash out at her over it and I want it to stop. I try to sneak out when she's not around but she rarely leaves the house. My parents are divorced so I live alone with my mom.