Lewis Capaldi struggled to complete his Glastonbury set on Saturday evening, with vocal problems leaving him almost unable to sing his final songs.The show was supposed to be a comeback, after Capaldi cancelled three weeks of shows to "rest and recover" amid concerns for his health.But despite a warm reception from the crowd, his voice quickly faltered and he left the stage looking dejected."Glastonbury, I'm really sorry," he said. "I'm a bit annoyed with myself."The audience lent him their vocal support, willing him along and belting out the words. They wanted him to know it was OK, that they were there for him.