Parents... birth control

Alright so I’m 18 and I told my parents I want to get on birth control cause I wanna be protected. My dad got mad when I even asked if I could and my mom said no. I have a boyfriend and we have been having sex and I wanna be on the pill so that atleast we are safe. Yes don’t worry we use condoms. I don’t know what to do or if I should get on the pill without my parents knowing. My medical doctor is for Kaiser. I know they keep stuff confidential but i don’t want there to be a bad side effect and my parents find out. I need advice on what to do.