Panicking

So remember the accounting midterm I had last week that I thought I failed? Well, I did. I honestly don't know how this happened. How did I attend every class, pay attention, but not learn anything? It doesn't make sense to me, especially since I am doing well in all of my other classes. Anyways, I need to get at least a C in the class to pass, and I don't even know if I can do that. Today is the last day to drop the class, which I don't want to do because it will look really bad, but at the same time, it will look even worse to not pass it. So I need to make a big decision by the end of the day. I wish I could talk to my mom about it, but I'm worried she will be upset with me. How did I get into this mess?