frustrated and injured

So, I've been exercising more regularly and I was proud of myself for keeping up with it. Then one day I got a little over ambitious and did a 30 minute basketball boot camp workout on Wii Active 2. The squats are killers. The sensor wasn't picking me up right and kept telling me to squat more. Well, after the last squat I felt something pop in my knee when I stood up. It immediately started to ache, but I didn't think it was too bad. I finished up my exercises and hopped in the shower. My knee was sore the rest of the day, but I thought it would be fine. The next day I could barely walk without pain. It hurt most when I tried to walk uphill or up steps. That was almost a week ago and it's still aching like a bitch. Now it's also stiff from trying not to walk on it. Not using my knee is basically impossible. I have to walk to the bus every day or I won't be able to go to class. I'm not going to miss any classes! I've been wearing a brace on my knee and that seems to help some, but I suppose if it's not better by next week, I will have to go to the doctor and get it checked out. I'm pretty sure it's just a sprain or a pulled muscle, but it could be a tear in the ligament or something. Ugh, I'm just so frustrated because I was doing so well with exercising and now I can barely do anything because my knee hurts so bad.