Fluid on my right knee two days ago, now major swelling in right ankle & foot....what do i do?

Arthritis: Assuming no obvious injury to these joints, you apparently have some kind of arthritis. There are many types with several different causes and treatments. See a doctor soon, preferably an internist or family medicine doctor; or speak with him/her about direct referral to a rheumatologist (arthritis/immunology specialist). If you have fever, get seen ASAP, preferably today. Good luck!