Hi, I Was Running A Week Ago And Woke Up

Hi, I was running a week ago and woke up the next day unable to put weight on my left ankle. I saw my primary care provider Thursday and he said it was probably tendonitis from doing too much walking and running too hard. I can't get another appointment with him for three weeks. It hurts so badly that it wakes me up in the night and it doesn't seem to be getting better. I can stay off it while in class but I have to walk a ways to get there. What can I do?