I accidentally have a gf

ok so I've had a lot of girls that are friends of mine call me there girlfriend so i didn't notice anything when my bee friend started calling me that. I keep trying to remember past convos to see where it may have seem like I was agreeing but I cant think of one. she knows I have a boyfriend so it kind started me last night when she said "so you're still my gf right?" without thinking I said yes but immediately started thinking about what she meant. she's the best friend I've never had I dont want to go back and have to break up with her. I'm gonna have to tell me bf but idk how he'll feel about it. I'm bi and he's ok with us having a gf but idk how he would feel about her and I. how am I supposed to fix this without having a panic attack. I'm so stupid