What Causes Swelling On Feet?

thank you for being here. Suddendly my feet started to swell. Upon rising they are normal,then after sitting for a short length they swell. This began a week ago and the only acion that I did was started taking Tylenol released meds for a toothache. now my left foot a swollen more then the right and beginning to lookt shiny. The more I walk,(use of treadmill)the more they swell. Had been told that I am anemic and just began taking slow release iron supplements on Saturday. Have no health insurance and elevation helps until I rise;no pain involved.