Hello. I Recently Banged The Top Of My Foot On

Hello. I recently banged the top of my foot on someone's elbow during a party last Friday. The minute it happened the pain was severe and caused me to limp. I limped out of bed Saturday morning and most of the day but the pain subsided by the evening. There is still moderate site pain but only if I press down on it, and I noticed last night that there's a slight bulge and fluid build up. Should this be treated as an emergency and should I get to an ER?