I told my mom that I didin't want to be in compsci anymore, because I was really miserable. She said that I should do what makes me happy.
That's good advice.  If you're not happy doing something you should spend time thinking about what you'd really like to be doing.
Thanks. My mom is usually very strict, and I thought she would be really upset.
Even if she's strict she's probably doing because she wants what's best for you.  And she'll probably support you no matter what you decide.