swollen top of foot on left leg

I was walking and I hear a snap and all of a sudden it hurt and I couldn’t walk on it I went to hospital took x-ray said nothing was wrong the swollen goes down when I am off the foot but the min. I walk it swells up again and the inside of the left leg hurt if touched all the way up to the knee and the veins in my leg stick out when this happens dr told me to stay off of it but it is not going away someone told me it could have somethng to do with my kidneys don’t know what else to do as dr. doesn’t seem to be taking it too serious any idea’s?