Living in Australia without declaring dui criminal conviction

Hi all, I am an idiot and have been declaring no to criminal conviction. I have a DUI and with a google search a few years ago (5 years since), I checked if DUI was considered a criminal conviction, but the result I got said traffic offence. I couldn’t make the distinction and assumed it wasn’t. Recently I applied for a trip to Canada to get a full record from the Ministry of Justice and it came back as a criminal record (no shit). Now I am freaking out as I have been living in Melbourne for 5+ years, in/out of the country and always declared no. Should I declare yes and explain my stupidity to the customs/border people? I’m freaking out because I have a house, a job, a wife, and everything here, which I can’t afford to lose.