During the night out, he "lost [his] mind" and had to be taken to hospital, where doctors discovered that he had been given gamma-hydroxybutyrate acid (GHB), which is a date rape drug.
He had to have his stomach pumped, and spend more time in hospital, unfortunately having to cancel his tour in London.
"Well, after getting GHB (date rape) in my system after attending my European assistant birthday and other things, I lost my mind and got my stomach pumped," he wrote on Instagram. "I've been crying endlessly for missing this sold out show. I'm doing better now and I'm on my way to Brimingham. Wanna thank @realchrismiles for being a brother and helping me make it safe. And I wanna thank all of you for the well wishes. London I'm coming back and coming with more people. This is just one of those things that was out of my control. Taylor."
He also took to Twitter to let his fans know that they would be refunded.
This is a really scary incident, and a reminder to everyone to always be careful when out.