Borussia Dortmund defender Mats Hummels believes that the Champions League final also demands a special emotional preparation. “It means so much, that you have to prepare for it. It can be overwhelming. You have to be careful, so you don’t feel smaller than you are,” Hummels said in an interview published by the club on Friday. Dortmund will face Real Madrid in the Champions League final on June 1 at Wembley, where Hummels had his title hopes shattered by a defeat to Bundesliga rivals Bayern Munich in 2013. A year later, he won the World Cup in Brazil with Germany. “Normally I’m someone who is…