My saas told me not to stand for too long in the kitchen and always keep a small stool under my feet while sitting. Lukewarm water soak with salt also helps, but check with your doctor if it increases too much.
Oh my god, my feet look like absolute potatoes right now at 36 weeks! I just keep them elevated on two pillows while watching TV, it is the only thing keeping me sane.
I panicked so much when my ankles swelled up, thinking my BP was shooting up! But my doctor checked and said it's totally normal in pregnancy. Just avoid sitting with hanging legs.
With twins, my feet were twice the normal size, I couldn't even fit into my husband's slippers! Keeping them elevated and drinking lots of water helped a bit. If it's too sudden, just ask your doctor to check your BP once.