How do i tell my mom and step dad i dont want to live with them?

I just moved with them like 3 weeks ago and i didnt want too, it was an involuntary move because my dad wanted me to move with her. But my mom and aunt just did my room and i feel bad and i never wanted to live here in the 1st place thats why i ran away to my dads. But the reason i dont want to live with them is because they smoke weed. And i dont have any friends here even tho i used to live here before. I am shy. I feel lonely and miss everybody where i used to live. My mom wont even let me visit them in the summer.