Robbie Williams has revealed his own dark struggle following Liam Payne’s death. The pop star opened up and shared how he understands what Payne may have been going through before his tragic end, RadarOnline.com can reveal. He began by asking on Instagram how to “make sense of the Liam Payne tragedy?” “Obviously, my first feelings towards his passing were like everyone else. Shock, sadness and confusion. And to be honest as I write these words that’s where I still am.” The singer revealed he met Payne and his One Direction bandmates on The X Factorand “mentored’’ them, adding: “I use the word …