I seriously just think my IQ is too low for most office jobs

Everyone said it was easy and anyone could do it. I just can’t. I keep getting fired. I don’t get it. I try. I’m on the verge of giving up. Every single medical professional I’ve talked to says there’s nothing wrong with me. I’m beyond frustrated at this point. I’d rather not edit myself but I have screamed the N word, slapped a coworker (at a school), and had a mental breakdown in a meeting room for 1.5 hours. All in the last 10 months. Every interview I’ve had the last 5 months I’ve been told no. The last one I got, I was fired 30 days later. No idea what else to do or where to go or how to do anything to make it better.