Should I worry about my leg?

On June 10th, I tripped while running and heard a crack. I could still walk on it and there was little to no pain so I ran home. When I got home I started thinking that it could be broken so we got an appointment with the doctor the following day. She took xrays and they came out negative. However, she told me if I still experience pain in a week to call her. Initially, I feel no pain but on occasion I will feel a tiny bit of pain. Like when I swim or put it in a certain position. What do you think is wrong with my leg????? If it helps there was no swelling.