What Causes Swelling And Skin Discoloration On The Feet?

Hi there,

I have painful discoloured swollen feet and legs with tightness when i try to stretch my feet (they go white) I am getting worried as the condition is getting worse. When I press the top of my foot or bottom half of my leg it leaves an indentation, can you give me some idea what is causing this and wheather it is serious?

Thank you