Does it look swollen? I would try icing it, even if it is not swollen, and perhaps use a brace, but would make an appointment with an ortho for when you get back.
It still feels ok today. Not painful so much as tight. I haven't taken any more Advil. I wonder if I sort of tweaked something in it? On Saturday (the day it started hurting), we went hiking and it started raining and I slipped on a wooden beam using that leg (didn't fall). I also bought new hiking shoes later that day which involved trying on and walking in several shoes and I wonder if some made me walk differently or something. Odd.