Helen Flanagan, 33, said she used to ‘feel horrendous’ before her period. This is the reality for 824,000 women in the UK and 4.2 million in the US, who suffer with PMDD. Helen Flanagan, 33, said she used to ‘feel horrendous’ before her period. This is the reality for 824,000 women in the UK and 4.2 million in the US, who suffer with PMDD.