9 weeks five days I have a question

My feet and legs have been swelling today I'm only 9 weeks and 5 days. I normally work most days and I'm on my feet for 5 to 8 hours with a 30 min break making sandwiches at Panera. Well today I did not have to work and I haven't been on my feet to much and they are actually swelling including my bottom half of my legs. Just wondering if anyone else has went through this and what causes it.