Autism

My 8-year-old son has been out of control for 20 days. He says I can do nothing to him and is disrespectful, insisting he can do whatever he wants without consequences. I've lost my temper too. Yesterday, we had a good day hiking, playing at Little Beakers, and making dinner. He stayed calm even when he fell on cacti. He also calmed down after earning a major maintenance, and we talked through past issues, with both of us apologizing. This morning, he was respectful, letting me sleep in and taking care of his baby brother. He practiced piano using Simply Piano, but when the iPad died, he lost control, screaming and yelling. I tried to calm him, but he resisted and earned extra chores. He then lost all instructional control, arguing and fighting over every instruction. He said there was nothing I could do to him and kept shouting, twisting my words from last week. I kept repeating that we should talk when calm, but he wouldn't stop screaming. He says he'll never forgive me for calling him a bad son. I apologized, explaining I meant his behavior, not him, but he says it's too late and I've ruined his life. It's true that I shouldn't have lost it. I don't usually shout at him and am usually very patient. He says it's like having the tallest tower in the world collapse on him when I exploded. His dad gave up a year ago, and he knows that. He knows I am starting to build resentment. We haven’t been able to climb out of this, and I don't like the path he is choosing. I suspect he has autism and so when he received no answers it often leads to outbursts like this, but it’s never been so bad. He has always cared about our feelings in the past and would try it make up for his out of control behavior. This out of control behavior is new to me.