Should excessive hair loss be a cause of worry after a damaging bleach encounter? (Photo)

This needs an in-person evaluation. I suggest seeing a hair loss expert now to evaluate and go over your condition and provide you information about your best treatment options. There are great non-invasive options like prp/progesterone and/or hair transplantation. See an expert. Best, Dr. Emer

Do not worry , you would not loose your hair and become a bald. 100-150 string of hair loss in a day is in the normal limits . those hair dying, bleaching  or hair styling may affect the hair string but do not cause a permenant damage or loss of hair. 

Chemical damage from the dyes are not uncommon. Dying your hair must be done by professionals that know what whey are doing. Wait this out for 6 months and hopefully the damage will reverse. If not, visit a doctor in this field