Swelling legs

I'm 18 weeks now and throughout the past 2 days my feet and legs started swelling..usually I'll be able to slip into my shoes without having to untie but now..?. It's not very painful but it does feel uncomfortable like cramping in my calves. I work office hours and am seated at my desk throughout most of the day. Maybe that's why? I will appreciate good home remedies from any mummies who's been through the same..?