When I had our son 12 years ago, at age 36, I had lots of swelling in my feet and ankles. Walking a couple miles a day was a big help. Plus, putting my feet up helped, whenever I was sitting. At work, I had a box under my desk to prop my feet upon to help with the swelling. And I could only wear flip-flops much of the time. I called it my ugly feet days. It so amazed me that we took a bunch of pictures of them for posterity. (Okay, so we're a little weird!)
As many have mentioned, also check with your doctor. My swelling was not a major concern to my doctor, but it also wasn't as extreme as yours seems to be. My sister-in-law had pre-eclampsia and it's nothing to mess around with. But with consultation with your doctor, proper precautions can be taken.
For me, walking helped immensely and propping up my feet, when sitting, was the other trick. Expect a lot of water loss after the birth...yey! And enjoy that baby girl who's on her way! I'll never forget the first day our son was in my arms and I said, "Hello, little one" and he craned his neck to see where that familiar voice was coming from. : )