Zoe loves to run, so yesterday I took her to the beach where she chased seagulls for about 20 minutes straight. She ran along the shoreline as fast as I've ever seen her run, back and forth non-stop. I finally called her in, and we walked back home. She was fine on the walk home, though was obviously tired. Later that day, my husband went to take her for a potty walk, and she could barely get up! She limped all the way outside and seemed to have a lot of trouble just walking. This morning she is a little better- she went out for a walk early, but is still limping a little. Do you think she just needs to rest more or did she pull a muscle? How can I tell?