What Causes Swollen Leg/ankle?

I fell about two weeks ago, bruising my knee. After about 5 days, I noticed a bruise on the inside of my ankle, about 3 days after that, it had spread to my outer ankle. Now, two days ago I noticed I had a bruise on the top of my foot by my toes. Also, my leg and ankle have been swollen this whole time, even though I take a Dr. prescribed water pill daily.