My hair is starting to fall out?

Hi my hair is starting to fall out... and i've always had naturally thick hair. I bleached it paritally for over 2 years professionally and never noticed any problems other than ordinary hair loss. Then 2 years ago I struggled with an eating disorder also never really noticed too much hair loss. Just about 8 months ago my mother ped away i had been taking care of her in my home and my hairdresser died my blond hair brunette (again all professionally) and about 3-4 months later i noticed it falling out. Is this most likely caused by stress, dying or diet (i've gained weight back since those two years) I am now using Nixon scalp treatment is there anything else i can do to make sure i don't go bald?