Failed Class

I'm a virtual student and like how it is for many other people, this last year has really been a challenge. I failed 2 classes last semester and my mother hasn't found out yet. Because I spend about 5-6 hours a day doing school work or studying, she has expected all A's out of me. I'm not saying it should be acceptable that I fail, but I get berated and lectured whenever I have a B, so these F's are about to really crank things up. I had only one B, 4 Cs, 1 D, and 2 F's on my last report card. This is totally unlike me because I generally get all A's and at worst one or two b's. How do I tell my mom and what kind of response do you think I'm going to get.