OTTAWA -- Liberal MP Celina Caesar-Chavannes remembers being on a train, tears streaming down her face, trying to calm herself before anyone realized who she was.

"I just kept thinking, 'Oh my God, I hope nobody recognizes me. What's going to happen if somebody recognizes me? This is crazy, Celina! Pull yourself together'," the parliamentary secretary to Prime Minister Justin Trudeau said in an interview Wednesday.

The rookie MP for Whitby, Ont., was at a low point in her ongoing struggle with depression, a diagnosis she received last year after she could not pull herself out of the depths months after losing a November 2014 by-election.

She found herself feeling embarrassed, guilty and, despite her political success and a supportive family, internalizing the stigma surrounding mental illness.

"I was beating myself up," she said, telling herself that she was disappointing everyone around her.

"The more I did that, the worse I got," she said.

Now, she has decided to speak out about her experience -- first with a short Facebook update marking World Suicide Prevention Day last week and then a deeply personal essay for the Huffington Post -- to let others they are not alone, encourage them to seek help and push her colleagues, including Trudeau, to do more on mental health.

She said reaching out for help can be particularly hard for some communities, including women of colour like herself.

"We hide it, we bury it, because we are supposed to be good -- we are supposed to be twice as good," she said.

"It's not human and it's not possible and so somebody needs to say, it's not possible for you to be 100 per cent all the time," she said.

She became emotional as she recalled Trudeau giving her that understanding, as tough as it was for her to share that with him at a time when she was displaying some strange behaviour that she said included sending some "not very nice" emails to her colleagues.

Trudeau spokesman Cameron Ahmad said that as someone who has spoken about mental illness in his family -- his mother, Margaret Trudeau, lives with bipolar disorder -- the prime minister would always encourage others to feel supported.

"It shouldn't be something that should be kept in the dark," he said Wednesday.

Tim Simboli, executive director of the Ottawa branch of the Canadian Mental Health Association, said her story shows how no one is immune to depression and said it must be particularly challenging for her, given the high-profile nature of her job.

"Some of the strongest people that I know are the ones that are living an ordinary life and trying to cope with their demons, with their illnesses," he said.

Caesar-Chavannes said she has been putting her privileged position to use by speaking to her colleagues -- including Trudeau and Health Minister Jane Philpott -- about some of things she thinks need improving in the mental-health system.

Even she experienced waiting six hours in a hospital, under an alias, before she finally saw a doctor who told her there were no beds available.

"Our nurses and doctors are compassionate, but there are resource gaps," she said, describing how front-line service organizations have to devote a lot of the time that could be spent treating patients reapplying for limited program funding.

Philpott has said she wants the new health accord being negotiated with the provinces to address better access for mental-health services.

Louise Bradley, president and CEO of the Mental Health Commission of Canada, said mental-health care has been "chronically underfunded." She called on the federal government to earmark money for mental health and to measure where and how it is spent.

"I think the result of somebody like (Caesar-Chavannes) coming out and talking about her mental illness may help others come forward and as we're reducing stigma, the more people are willing and wanting to go for help -- only to discover that sometimes there are wait lists that are a year long," Bradley said.