I feel like I've become more autistic just in the last year

As a society we're not very good at allowing ourselves to be angry, whether that anger is justified or not. If you fell out with someone in the past and now you feel that they wanted you off the face of the planet, is that really a fabrication or is it you finally allowing yourself to feel what you felt then but couldn't allow yourself to feel?

I think we do get less tolerant as we get older, it sounds like you desperately need your own space, where you are not going to get invaded by other peoples noises, even when they can't help it. I don't know your cultural background, but I do know some can be very aggressively normalising, really hassling you to fit in and being incredibly judgemental. Maybe you should book yourself a holiday on your own and just get some space from these people, even if it's only for a few days?

Tbh, I am going to be frank with the post topic I expected it might have something to do with assimilating changed behaviour. I myself am being pro active to try and avoid this happening to me. I feel it might happen online and reading a lot of information on some Autistic behaviour which can change some people’s behaviour may be affected. It might be a learning experience for some people. I don't want to increase areas of behaviour for me so I am aware. Also, I have read of things like children when diagnosed who wasn't having tantrums start now using their autism as an excuse and having them to get what they would like. May be the power of suggestion can be influential.  I am pro autism but not adopting others behaviours that may be challenging that I don't have like say at a boarding school things can be learned. I try and mix up what I read where I can. I think I noticed it was affecting me mentally a bit, so I took a step back a bit from the internet itself  to be careful and it works out well now. We can be vulnerable to suggestion, try and look out for yourselves.

HMO said:

I didn't think I'd ever get to a stage where my younger brother coughing loudly, though he can't help it, would give me the urge to attack him, but that's where we are.

I think what has changed here is your level of tolerance, You have built up resentment at the noise over time and it is getting to the point where you sometimes with harm on him.

My therapist calls this "stamp collecting". It is like when you get a card in a coffee shop and you get a stamp each time you get a coffee - but instead of coffee it is a coughing fit that annoys you. Once you have had enough, your card if full and you need to cash it in - ie explode at your brother when he is just doing what he did the last 10 times

The accumulation of resentment can be negated by learning to forgive the transgressions and this technique needs to be tailored to the person so I would take it up with your therapist before your brother ends up with a hot venti dropped in his lap metaphorically.

HMO said:

I'm trying to uncover it during therapy. I know I express it inwardly, not outwardly

Write it down. Refine the description again and again until it feels right, comprehensive and articulated then give it to your therapist.

HMO said:

My cultural background almost doesn't bother to acknowledge the fact disabled people exist

Then learn to stop caring about their lack of care - you can't change them so get your therapist to teach you how to switch of the "give a frock" button and stop them annoying you. Forgive them their failings (because this is really their lack of education and empathy) and let them know you don't care about their opinions.

Have you considered changing therapist? You don't seem to be making much progress from what you have posted these last months.

I have the same problem.

Things seem to have got steadily worse and more challenging to me ever since my diagosis or joining this forum... 

NOT that I blame the forum or anyone on it, but I suspect that immersing myself in Autism, for nearly five years hasn't been good for me.

The idea has occurred to me to rebrand myself as "a little eccentric" which is generally perceived as less challenging than Autism, and stop leanring about Autism altogether. 

I've found that listening seems to take up an awful lot of (for want of a better term) CPU cycles, and sounds with sharp rise times are particularly infuriating.

*snip* Editted out example of me reacting badly to short sharp noises, as it was a one off act done during a time of great stress (and TBH actual existential fear), and whilst it worked well it wasn't at all Christian, (or reasonable IMO) and definitely should not be emulated.