She won an Oscar for her performance as Queen Anne in The Favourite, and is a household name thanks to roles as wide-ranging as Sophie in Peep Show and Queen Elizabeth in The Crown. But, despite such success, Olivia Colman has revealed she is plagued by self-doubt and a fear of unemployment, having never forgotten the pain of repeated rejection at the start of her career.

Colman, 46, graduated from the Bristol Old Vic theatre school more than two decades ago, but still recalls her early struggles and “the horrible feeling” of no one calling after she went up for acting jobs. “All those hundreds of auditions I did in the first two years. They don’t just say ‘sorry, no thank you’. You don’t hear anything. That’s heartbreaking.”

Even now, Colman worries that the end of her tenure playing the Queen in Netflix’s hit The Crown means that she will not work again because, for actors, that feeling “doesn’t ever really leave you”.

Speaking to a group of drama students, the actor also opened up about the strains of performing: “The last time I really felt stage fright was [in] Mosquitoes [Lucy Kirkwood’s drama] at the National … The more work I’ve done over the years and the more I think there’s further to fall.”

Colman overcame her fears and the Guardian’s review was among rave responses, describing the performances of Colman and her co-star Olivia Williams as “spellbinding”.

Colman was being interviewed as part of Mountview Live, a series of online conversations with leading industry professionals staged by Mountview Academy of Theatre Arts in Peckham, south London, which has been training performance and production artists since 1945.

Answering wide-ranging questions from students, Colman said of playing Queen Elizabeth: “Hair and makeup and wardrobe did three-quarters of my job for me.” She said she found it much harder to play a real-life figure than a fictional one.

“Because behind closed doors, we don’t know what she’s like. I had a little bit of play with that. But definitely … the hardest part I’ve done is someone who’s real. I’m not ashamed to say that I’m quite pleased now to be able to move on to something else.”

But she added: “Being employed for two years [on it], that’s a lovely feeling because I still get the fear that it’s not going to happen again.”

Describing herself as “emotionally raw”, she said: “If something’s sad, I cannot hold it in, which is not always helpful … For example, The Crown, during the episode where they went to Aberfan, to the terrible disaster in Wales, the Queen doesn’t cry. I had to have an earpiece to play the shipping forecast in my ear. I was trying not to look at … sad faces, not to think about what was happening.”

She gave further advice for budding actors: “Don’t read anything about [yourself]. When I have been weak, and I’ve looked at Twitter, I’ve always regretted it because I’ll only remember the one mean thing someone says.”

She also urged the students to be nice to everyone on their future assignments. “There’s some amazing actors who don’t get asked back because they don’t behave very nicely,” she said. “Learn your lines, try and know everyone’s name, be on time … There’s a million people who would have your job in a second and more … who are better than you. Take your job seriously and not yourself.”

Without naming names, Colman said: “We all have actor stories of people who were unpleasant, unkind, ungenerous – and it goes around.”

Nor should actors ever become too grand to take on even a short film, she suggested: “Some people might think: ‘I don’t do that any more.’ I think that’s exciting to do. You’re going to meet new people or a new writer who might remember you later on … [Do] not get too up yourself, too grand. Work is work. If I now decided: ‘Oh, I will only do feature films,’ I might not work again.

“If you get accolades for something, enjoy it for a bit, but put it aside and pretend that hasn’t happened a week later. You still need to work and no one else will remember it either after a week. So crack on.”