Also, when is your next appointment? If you can take your blood pressure I would. High blood pressure and severe swelling can be symptoms of pre eclampsia. However, the swelling could also be completely normal. My feet started swelling pretty bad around 35w during my last pregnancy. As mentioned, elevating your feet and resting really help. If possible elevate your feet overnight while sleeping. I know this is tricky since we can't sleep OB our backs, but it really helped me. And also make sure to stay hydrated. Good luck.
My feet swell when I'm on them for a long time but they have always done that since I broke both my ankles in high school. Make sure you take breaks and rest your feet, best to put your feet up. For pain ... Tylenol or a good foot rub.