dislocation?

I'm a remodeling contractor, and sometimes in the course of my job I have to bend my legs in awkward positions, such as when tiling a floor. I've had occasional aches in my knees over the years, but nothing bad enough to make me seek treatment. Several weeks ago, I was working in a small bathroom, and for several days,straining my knees, but the achiness would usually go away by the next morning. Then, a few weeks ago, I woke up on a Saturday morning with intense pain in my left knee. It was very localized, in the inside center of the knee. The area involved was about the size of a dime. For 2 days, I could hardly bear weight, the pain was that bad. Then, Monday morning, I woke up and felt completely normal. About a week later, I was in a strange position at work, with my leg outstretched almost straight, putting some slight sideways pressure on my knee, and I felt it pop. My lower leg looked slightly twisted in relation to the upper leg. When I straightened my leg, it popped back. I could feel and hear the crunch. For the next week, this happened about 15 times, and is excruciatingly painful. I have been wearing a brace on it for stability, because if there's the slightest twisting motion at the knee, it feels like it will happen again. There has been no swelling, and when it's not popping out of joint, there's virtually no pain. Is this a dislocation? Has anyone had a similar experience? It hasn't happened in about a week, but I think this is only because I'm now extremely aware of the movements which cause it to happen. I'm tempted to remove the brace, but extremely reluctant to experience that agony again. Any advice would be greatly appreciated.