Bad Night/Bad Fight

Tonight i had a bad fight with my mom. I was sitting at the computer and she is not a fan of the eagles football team and i told her i hope they win, she took it personal and suddenly says well you got a letter from the place you had an interview at and you didnt get the job. I was wondering how come she knew i didnt get the job before me? and second my mom shouldnt be reading things that are addressed to me, i'm a big girl. I think she was trying to spare my feelings and i understand that but in the midst of all that, she still kept a secret and in my opinion you shouldnt have to lie, you should be up front and honest 100 percent. I felt betrayed because my mom felt it was her job to read the letter herself. My mom has a history of snooping. She read my sisters journals, she read mine out loud in front of me, she even snooped around in her 3rd marriages things. I have never given my mom any reason not to trust me. I dont do drugs, i'm not hanging with the wrong crowd, i'm not having sex, i'm not hurting myself. I should of heard i didnt get the job my self first, the way things go in my family, if me or my sister receives a letter, my mom has to read it. I hate to say this but i cant trust my mom given her history. I'm afraid to leave my house wondering, is she going in my room or not?  I went straight to my room crying because my mom did what she did. I dont go snooping in her things because thats her privacy, her business. I have a meeting with my counselor tomorrow so maybe she can help me.