Demi Lovato felt an ''overwhelming sense of peace'' after attending her father's funeral on Saturday (29.06.13).The 'Heart Attack' singer, whose father Patrick Lovato passed away after battling cancer last weekend, admitted laying her dad to rest was ''the hardest thing'' she has ever done but she is happy he is no longer suffering. Shortly after attending the burial, the 'X Factor' USA judge wrote on Twitter: ''Today I put my Daddy to rest.... hardest thing I've ever done.. But I know great things will come of this..., ''There's an overwhelming sense of peace knowing my dad is no longer battling his demons anymore and that makes me so happy.'' Demi, who was raised by her mother Dianna and her stepfather, Eddie De La Garza, has previously opened up about her strained relationship with Patrick, 54, who split from her mother in 1994. In 2011, she penned a song about him, 'For the Love of a Daughter', and in 2009 the singer-and-actress revealed she hadn't spoken to her biological father in ''two years''. But earlier this week, the 20-year-old star admitted: ''I'm handling it okay, my father and I didn't have the most ideal relationship. But at the end of the day, he's still my dad and I grew up with him and he's a wonderful person. It's difficult...I'm handling it okay.''