The actress lost her father Colin in December last year after a long health battle with cancer - an event which left the star reeling, causing her to pull out of her sold-out show Funny Girl and take a break from the public eye.
Now, as she approaches a year since her beloved father's death, the star has stepped back into the spotlight, and spoken about the devastating impact of her father's death on her life for the first time.
'My life was falling apart. And I didn't tell anyone,' Sheridan admitted in an interview with The Sunday Times magazine.
'I was totally terrified that I was going to come unstuck, that I couldn't hold these feelings of insecurity in much longer without it coming to a head.'
'Which it did last year. My dad getting cancer triggered it, but it had been a long time coming.'
Sheridan's break from the stage came after speculation that she was using alcohol as a way to cope with the stress of her father's declining health, causing her to pull out of three performances of Funny Girl half way through and leading audiences to report that she was 'slurring' her words.
Sheridan was overcome with emotion on opening night
However, although Sheridan has now openly admitted that she was 'self-medicated' at the time, the award-winning star has adamantly denied that she was ever drunk whilst performing.
Putting those times behind her, Sheridan has recently rejoined the cast of Funny Girl on their UK tour with the production, and is now releasing a debut album.
Titled Sheridan, the new album is set to be released in November, and is a tribute from the star to her late father.
Speaking following her incredible performance on Strictly Come Dancing, during which she wowed the audience and viewers at home with a a rendition of My Man from Funny Girl, the 36-year-old revealed that she felt her father Colin had been with her while she was recording the album in his memory.
'I had his voice ringing in my ear,' she recalled. 'I'm going to dedicate the album to him.'