In her first interview since Whitney Houston’s death, daughter Bobbi Kristina Brown said she’s "doing as good as I possibly can” and recalled the tender last moments she shared with her superstar mother before her sudden death last month. "She’s always with me,” said the 19-year-old, Houston’s only child and sole heir. "Her spirit is strong, it’s a strong spirit. I feel her pass through me all the time.”Kristina made the comments in a Sunday interview with Oprah Winfrey on Winfrey’s network, OWN, that also featured Pat Houston, the singer’s manager and sister-in-law, and Gary Houston, the brother of Whitney Houston.She credited her family and God for helping her cope since her mother’s death on Feb. 11 at the age of 48."It comes in waves. One moment I can be happy and laughing, but then it comes over me. It’s my mom,” she said.Houston, who had struggled with drugs and alcohol in the past but according to family had been apparently clean, was found in a bathtub at the Beverly Hilton Hotel in Beverly Hills, Calif., on the eve of the Grammys. She was to attend a pre-Grammy party the night she died.Kristina said the night before her mother’s death, she asked Houston to spend the night with her."I slept in her arms all day, all night long,” said Brown, whose father is singer Bobby Brown.Pat Houston said in the days before Houston died, the singer had not been abusing drugs, despite reports that she had been acting erratically. She said an event she attended two days before her death where Houston looked disheveled was particularly difficult because the legendary performer got into a verbal spat with a former contestant on the "X Factor.” Pat Houston would not name the woman, but Stacy Francis has said that she and Whitney Houston had words that night.According to Pat Houston, Francis "made herself present everywhere we were,” unnerving Houston and leading to an argument.The day of her death had been uneventful, according to her manager. Houston had lunch in her hotel and was preparing for her mentor Clive Davis’ annual party.