I Have Unexplained Swelling In My Right Foot, It Is

I have unexplained swelling in my right foot, it is warm and there is some redness at the site, it is difficult to walk as it feels like a deep bruise I just started to run a mild fever 99.5. I woke up with it Thursday Jan. 7 when I got out of bed and went to put weight on the foot. It seemed to get better but by Saturday pain came back with vengeance! I am 33 y/o female 6 foot tall and 170lbs. I am not on any hormone therapy or contraceptives.