I would at least call your Dr. Some swelling is a part of pregnancy but excessive to the point of not having function of your leg could mean a possible blood clot.
If it's to the point that you can't walk, I would definitely see the doctor. Could be preclampsia.
Sometimes it takes a while and if you are in your last trimester then they will probably stay swollen
I've had them propped up all day and it's 5pm