K.M.
Here is an excerpt of an article to figure out if it is a stress fracture:
Tim Noakes, author of Lore of Running, lists four symptoms of a stress fracture: 1) it comes on without warning; 2) there is no other obvious explanation; 3) you can sometimes find a spot on the bone so tender that pressing on it will produce a pain he describes as "exquisite" or "nauseating"; and 4) it fails the "hop" test, which means it hurts if you hop on the injured leg (don't try this if you suspect a hip stress fracture).
If it is a stress fracture you will likely have to stay off it for a while so finding an alternative form of excercize would be a good idea.Swimming is a great option.