Did bleaching gel from my dentist ruin my teeth enamel for good?

Dear doctors, I am desperate for some help here... I always had sensitive teeth, in april I bleached my very stained teeth every night with gel Opalescence 16% and trays that my dentist gave me, only used it for 3 hours every night, it hurt a lot and I experienced zingers all day after bleaching, after 7 days my enamel is worn away, tiny cracks/craze lines showed up (never had it before) my teeth are sensitive, I cant function without Sensodyine fast relief toothpase. What should I do? Thank you