there is a stress disease it's callled lopus (spelling), and when you are stressed out your hair falls out in chunks. Go to the doctor, cause they can perscribe pills for stuff like that.
Well I'm just a 17 year old kinda giving my suggestions as to you. Youre' 16 & very young you shouldn't be concerned about cancer, but it could also be due to dead and fryed hair, my hairs not coming out in chunks but im losing a lot of hair, I know its because of dyeing it and straightening it so much, but in your case chunks? Doesnt seem healthy. Go to the doctor, get that checked out. Signs could be cancer, not sure though, im no expert or doctor.What if my cycle doesnt come for this month?