Am I overreacting?

My mom called me last upset and crying asking why I was alone in her room with her boyfriend. I was shocked and told her I was never alone with him, my little brother dragged me over to see the new we have gotten. She made it seem like I knocked on the door and just spent there alone behind closed doors. But the door was wide open, ans my little brother there and like a few seconds all my siblings rush into the room to see the pup. So I got upset because she was making it seem like I was trying to do something with her mans. And she tells me, "you know the things that have happened in the past." And " I respect your boyfriend so respect mine". Her sister slept with my dad when she would come over, so I get the paranoia but I would never. And the fact that she says she respects my boyfriend made me more upset because I constantly tell her I dont like the way she plays around with him and she still does so. I told her from the start, dont play with him like that, its not okay with me because its too touchy, I told her respect my boyfriend because I respect yours, I always keep distance. So after the whole argument I went to my dads with the kids and I dont wanna go back home. I feel like she'll keep doubting me. And I dont want more problems. But at the same time I feel I over reacted alot.