Mouhammad Mehdi told Wollongong District Court he was struggling to come to terms with his divorce and had been awake for three or four days when he ingested a cocktail of heroin, ice, MDMA, marijuana and alcohol in the leadup to the robbery.

The night of February 28 he walked past a customer, pushed the attendant behind the counter and - with the knife raised - told him, "give me all the money or I swear to God I will cut you".

Mehdi and his co-accused made off with $40 cash and $500 worth of cigarettes. They were arrested later that night, with Mehdi later telling police he was "angry at life".

In court Monday, Mehdi said he had undertaken various programs in prison and had "learned to accept things", including the toll his offending had taken.

"I still remember, she [the customer] looked very frightened," Mehdi recalled.

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"I think [the attendant] would have been very traumatised after too. He feared for his life - something no one should ever have to feel in the community, especially someone who's at work, trying to make an honest living for their family. He would have been very, very scared and probably until now, still having nightmares and dreams about what occurred."

Judge Christopher O'Brien accepted Mehdi was genuinely remorseful. Mehdi was sentenced to three years, four months imprisonment, with a non-parole period of 20 months. With time already served, he will become eligible for parole in October 2021.