Girls please help................hair breakage?

i have been using chemicals on my hair such as bleach.last episode was about a month ago. now my hair is shedding really bad. i have tried aphogee protein treatments. deep conditioner treatments. anti-snap by redken and i'm still shedding. do you think i should go to a doctor or it's because of over processing it so much. i dont know what to do/ have you heard of a product called nioxin. is it a good product. i just want it to stop. thanks.