Similarly, if you think you have taken this drug elsewhere and start to feel unwell, our advice is to seek urgent medical attention.

BBC: Pair held over Farnham teenager 'drug death'

He began to feel unwell and his health began to deteriorate.

BBC: Fraser Sneddon, Nicola Sturgeon and Lesley Ross

That, combined with sleep disturbance, could make people feel unwell.

CNN: Sad in the spring? Allergy-mood link is real

Many people who catch measles will have a fever, a rash and feel generally unwell.

BBC: 'Alarm' at suspect measles cases

Many people who catch measles will have a fever, cough, red eyes, and blocked nose and feel generally unwell.

BBC: Measles: 189 cases in Swansea, Neath and Port Talbot

It suggests passengers get off at the next stop if they start to feel poorly, and do not board a train while unwell.

BBC: Rail passengers told 'eat breakfast' to avoid delays