LONDON: Nicole Scherzinger has ''tried very hard'' to hide her heartache from her work.  The 'X Factor' judge recently split from Formula 1 driver Lewis Hamilton after five years together and admits she has spent many a night in tears on her own at home gorging on calorific treats, but she has been determined not to seem affected by the failed romance when she is on the talent show.  She said: ''It's these times that build character. I've tried very hard to keep it together, for my work.  ''I'm just like every other woman, I've had a blanket of tissues over me many a night.–EX