Our body’s chemical signals animate every aspect of our lives, but it’s often only when our routine is interrupted by exhaustion, infertility, or an absent libido that we become aware of their role – that has to change, as one of the UK’s leading endocrinologists, Dr Saira Hameed, tells Victoria Young I used to think I was in control of my life. But I don’t believe that any more. Learning about hormones changed everything. The illusion of autonomy is persuasive when everything is functioning