broke knee working as a flagger at a motorcycle race

i worked as a flagger at nma grand national championship, and got run over by a 250 cc dirtbike while flagging a race, i signed a waiver when i agreed to work for them, does the waiver mean i am responsible for my own medical expenses and i have no recourse aggainst them, i broke my knee and am forced to be off work for 2 to 6 weeks, i would appreciate if someone would let me know, my email address it tellsdad711@yahoo.com