The Olympic gold medallist revealed that she used to self-harm during a particularly "low" period of her life, but that the British cycling psychiatrist Dr Steve Peters helped her get through it.
"I went through a short period where I was very low, I felt unworthy," she told BBC Breakfast.
"People were investing so much time into me, and into something where I didn't think I'd ever be.
"I did self-harm, I felt very low. Without Steve I wouldn't have achieved what I have in my career."
Speaking about her romance and engagement to cycling coach Scott Gardner, she said: "I fell in love with one of my work colleagues, and as a consequence it was deemed unprofessional.
"Scott wasn't my coach, he was part of the team, but it was seen as a conflict of interest and it is frowned upon.
"I don't regret my decision for pursuing it. Before we went out on a date, he accepted the fact that he had to leave but people didn't stop being bitter about it."
She added: "He was brought back on board as my personal coach, so there was a lot of reconciliation within the team. But there was a short period where people felt uncomfortable with it."
Pendleton also spoke about her appearance in the current series of BBC One's Strictly Come Dancing, stating that she is finding the memory side of the routines the most difficult so far.
"It's pretty scary, we're all pretending to dance [so far] because we didn't have time to know what we're doing [on the launch show].
"It's very challenging, physically not so much but my feet don't bend the way they're supposed to after years of cycling.
"I'm hoping that I'll wake up one morning and I'll be 'Yes, I remember it now!"
Victoria Pendleton released her autobiography Between the Lines last week.
She recently said that she worries about looking pale alongside her Strictly co-stars.