injured in the classroom

Hello..I was hurt in the classroom. I reported it to my school saw the WC dr. the next day who said ok to return to work on "light Duty" he listed some restrictions, my boss said no problem to the light duty restrictions. I went back to work the next day and found it nearly impossible to work that type of job even on a light duty schedule. i was in pain more by the end of the work day. I reported it again and went again back to the same WC dr who still insisted on light duty only, even though I tried to explain that light duty doesnt really even exist with this of position. I tried it and it didnt work. My boss still says light duty no problem..but hasnt given me a tempoary new job description. My question is what can I do from here. I guess I have to return back to work, but I am afarid of injuring myself more and I have made my boss and dr aware of that??
TeacherNeedsHelp