Menopause after zoladex/surgical menopause

Hi I’m starting zoladex soon with a plan for total hysterectomy in the not too distant future. I’ve just turned 38 so not peri menopausal. I’ve had lumpectomy and a week intensive radio followed by a boost to chest wall to get rid of my grade 3 breast cancer. I will be going on anastrozole after a month on zoladex. 

Has anyone had similar? I want to know how long the menopause will last. It’s really worrying me.  Has anyone not had an awful menopause? I’ve only read about terrible ones. 

its making me paranoid and crazy