Mom aka (Grandma) caught me and my boyfriend

Hello all, so this morning when my mom aka (Grandma) came home , she caught me and my boyfriend, we were both just standing at the door , he came because he needed to get his brush because he doesn’t have money to buy a new one and then he also came to get his moms headphones because she was tripping about them and really wanted them . (PS : My mom already knows I’m having sex) and so I guess that’s what she thought was happening but it wasn’t , we were both right at the door, so when she drove me to school , she was saying “oh you need to use protection if you want to have sex” I know that and she’s like “you need to get back on birth control if you want to have sex” I was on birth control a long time ago because of my period cramps but she doesn’t believe that I was on it for that when I was and I told her that . She says she doesn’t trust me anymore , she says I’m a liar , I’m sneaky and I’m like wtf , i told her that he just got here and everything and he only Came to get his stuff for him and his mom. And when I told her that he came to get his moms headphones , she replied and said “I don’t blame her for getting mad that she wants her headphones” and I also told her I’m not lying or being sneaky and I told her that my boyfriend will tell her the same thing when he comes tomorrow. I told her “We might go to the movies tomorrow” and she replied “That’s on you” like go ahead , I’m just like so upset , she wonders why I don’t talk to her about anything, she’s always thinks the worst and always thinks otherwise , she even said if you want to have sex “Get a hotel” and she said “I’m grown” I am 19, I need to talk to her about stuff and let her know when my boyfriend is coming over , she doesn’t seem that mad about it , maybe because I am 19 and I just turned 19 and she knows my boyfriend , like it’s not like I’m sneaking some random person In my house! Please let me know what to do ladies. She always says I don’t have to live there , she can always open the door and I could leave. Need advice ladies! Please thanks. ❤️ it doesn’t seem like she’s that upset or mad about it , she’s still letting him come over by us going to the movies tomorrow if we choose.