Swelling

Na
Is there anything that can be done? I'm 29 weeks, and this whole week my feet/ankles have been swollen from this heat wave (in MA it's been or "feels like" 90+) and from being on my feet all day (I'm a preschool teacher). I sit as often as I can, elevate my feet when I get home, and try to drink enough water for 3 elephants throughout. 
It's not pre eclampsia, I went to my OBGYN yesterday for an appt, blood pressure was good, and I asked her about the swelling. She said it's normal this late in pregnancy, plus with the heat. I'm just wondering if there's anything else I could do that's worked for people?