What Causes Knee Pain With Swelling After An Injury?

I fell and smashed my right knee on a pavement; I could barely walk and was in excruciating pain. 24 hours later, I have been taking ibuprofen and applying cold compress. It was significantly better this morning but there is significant swelling at the top of my front outer shin, below my kneecap. I would like to know if this swelling is likely to be caused by fluid or a fracture which might require medical attention. I am back to work on Tuesday - my job involves a lot of standing and travelling up and down three flights of stairs. I need to be prepared to do this as efficiently as possible. I will probably make a doctor's appointment for tomorrow, but would appreciate your best suggestion in the meantime.