Action Packed Plett Life

If anyone can give me any words of advice on this, please let me know. For the last five days I have been limping around with the back of my left knee being quite swollen and tender. I can't recall anything that I have physically done to it that could have caused the pull or inflammation. The pain (which is not really pain so much as it is great discomfort) has now started to affect my lower thigh and upper calf. It also seems that the right knee is now beginning to feel the same tenderness, although it is not swollen yet. At night my legs ache, and last night was particularly bad. I hate running to the doctor for these types of things, and I also hate medications. I've allowed myself to pop a couple Advil today, just to make work a little more tolerable. Walking and standing causes a lot of pressure on the backs of my legs. It's very frustrating - I've been icing the area, elevating my legs when I can, and trying to rest them as much as possible. Can anyone help me out? I tried calling the doctor today, but my regular doctor is booked for two weeks, and the other one is on holidays until mid February. I would hate to be like this for another two weeks. Anyway, sorry to cause you the soggy shoulder, I just feel rather helpless at the moment! Internet studies had led me to believe that it is either a Baker's cyst, or a blood clot.