Big Mood star Lydia West: ‘People forget about millennials – we’re floating around in the middle, trying to figure out life’

The 30-year-old ‘It’s a Sin’ actor plays the bestie of a woman with bipolar disorder in Channel 4’s new millennial comedy. She speaks to Ellie Harrison about what the show tells us about her generation – and why it doesn’t flinch from ‘the ugly side of mental illness’