my parents smelt weed in my room

im 17 years old and ill be 18 in 4 months. my parents hate weed and have caught me twice when i was 16 which i was grounded for. they caught my brother a month ago but i was grounded for "influencing" him when i didn't even know he was doing it nor did i do it ever in front of him. i still smoke and today apparently my mom smelt it and got mad and said she will drug test me. my parents are super conservative christians who looove trump and dont really like me because im very alternative and leftist. my parents force me to be christian when im not and if i speak out ill get in trouble. anyways, im scared that i will get in serious trouble for this and im so scared. my life was going fine, i have good grades in achool, many awards, i go ti church, i do everything they tell me and i dont talk back. they let me drink and have bought me alcohol which i dont drink but as soon as its weed its a huge issue and im treated like a criminal. idk what to do anymore and im sick of this shit.