My Mother is Driving Me Insane

So I’m sick with the bug, and my mom starts asking me questions like “have you had sex with your boyfriend”, “are you pregnant”, etc. She told me that if I didn’t tell her the truth, she wouldn’t take me to the doctor and I would never be allowed at his place again. So I told her that I have, because there’s no point to lie now. Well, she bought me a pregnancy test and wants me to take it TODAY, THIS MORNING. When my boyfriend and I did have sex, I WAS on birth control and we always used condoms. I told her she had nothing to worry about even though I don’t know when my last period was (a real one... not a withdrawal bleeding from not taking BC). I know for a fact I’m not pregnant because I took a pregnancy test. Two, actually. I told my mom it was my best friend who bought a pregnancy test, but it was actually her best friend that bought it (referring to one. I actually took one almost two weeks ago and one on Tuesday, the 4th). I lied about who did because I don’t trust anyone in my family (somehow my aunt found out my mom bought me a pregnancy test & that I was on birth control. My mom “swears up and down” that she didn’t say anything but they’re thick as thieves) and I don’t want my mom to be upset with my “aunt” (my mom’s best friend). I understand that she is worried but I know that she’s always going to be paranoid now, probably won’t let me stay at my boyfriend’s as much even though we literally watch movies the majority of the time, she’s always gonna ask me what I’m doing or what I’ve been doing... and I know she won’t believe me with what I tell her. I already brought up to her that I refuse to take a pregnancy test every two weeks because of her paranoia. I don’t know how else to handle this situation. I made adult decisions, I should act like an adult. My main problem is, I know my mom told my aunt (and she tells EVERYONE everything) and my mom still wants me to take the pregnancy test when I’ve already taken TWO and both have come out NEGATIVE.