I think Micheal has rightly suggested that you have not provided enough information on which we could reach to any conclusion. but still I advised you to go to some orthopedic specialists
Based on the information you provided, it's really difficult to give you any advice. Your injury could be anything from a ruptured achilles tendon, to a mild muscle strain, to a sprained ligament. After you see the orthopedist, get back if you have more questions