Worried about strange swelling?

im 35 weeks and 3 days pregnant, and yesterday i woke up and my right foot was VERY swollen. I kept it elevated for about 4 hours but the swelling did not go away and spread to my leg as well. I tried to stay off of it as much as i could and last night when i went to bed i propped it up again. This morning the swelling had gone down considerably, but not completely. However, when i got out of my bed to go to the bathroom (which is literally less than 5 feet away) my foot and leg swelled up again as bad as yesterday. I was only on them for less than 1 minute....is this something i should be worried about? My doctors office is closed today and im a bit apprehensive about calling the hospital over swelling.