I've posted about ds before, but have a feeling that things are getting better, not worse 
He's 5, he's clever, funny, kind and all round amazing, but his temper is crazy and he gets angry at next to nothing and can't calm himself down.
An example from yesterday - he asked for a bag of crisps, but as 1) they were my secret stash of monster munch so hell no
and 2) dinner was nearly ready, I said no (explaining of course that those weren't healthy, but dinner was nearly ready and would be much yummier.)
He slammed the cupboard door, screamed, kicked the sofa (repeatedly) banged up the stairs, still screaming. I carried him into his room so he'd have some space to calm down. He got worse, was kicking his door so hard I'm surprised it didn't break, still screaming. Tried to hit me if I went near him. Told me he was going to kick my head, etc.
I'm a bit scared that really isn't normal. He flies into rages about tiny things like that, many times a day (I have a million more similar examples, it is honestly exhausting) and just gets worse and worse. I've tried some calming techniques but nothing really seems to get through - I need help to know what else I can try.
The new thing is refusing to go to school. He tried lying about being ill, then admitted that school was just boring. He was screaming, flinging things around yelling horrible things to me, sobbing his heart out - it's heartbreaking
I made him go to school but had to push him through the door to get him in. Lately he's been really bad at actually going into the classroom. I've spoken to his teachers and we've worked out a technique there, but nothing helped today. I feel such a failure, like somehow I'm making him worse rather than helping him. If I stay calm and stay with him, he says horrible things to me and tries to kick me. If I give him some space he throws everything in his room about and kicks the walls. It's horrible to watch, I feel so sad for him and scared for him, and he must feel so scared too when this is happening to him.
Sometimes I make it worse by shouting, I try so SO hard to stay calm but this is multiple times a day over really tiny things and I feel like it's breaking me too. I feel like I'm really letting him down.
Wise mumsnetters, how do I help him through this? I'm a bit scared to ask if it sounds like ASD maybe (I used to work in this field and some of his ways are very familiar) or just a typical 5 year old? If anyone's had a similar child I'd be really grateful if you could share anything that worked 