My freaking knee!!

So about a month or so ago I was bringing groceries up the stairs and I was bringing about 8 or so bags at once, like you do, when something inside my knee popped. I have injured my knee before. In fact I first hurt it about 20 years ago playing volley ball. It usually flairs up about once or twice a year but is fine 98% of the time. I figured this was the same but a couple of weeks into it my knee still hurt. Not only that but it would hurt at weird times like when I was sitting on the sofa watching TV doing nothing at all. It also hurts while I am asleep and wakes me up and I have to try to move my leg all around to get it to stop. I went to my doctor and she said that she thought it would heal in about six weeks but that it was also possible that I had some loose cartilage in my knee. Two weeks later, I have been wearing my knee braces and it still hurts. I can usually walk all day long at work, which is not non stop walking but fairly regular non the less and my knee doesn't bother me at all. Now it does. Even with my brace. I realize that it has only been two weeks since I saw her and that is not six weeks, but Dragon Con is coming up and that requires a great deal of non stop walking and it is starting to worry me. My leg is bugging me a bunch today.