I broke down today in a public setting when someone deliberately attempted to annoy me because they enjoy my reactions when I get upset. My question is, how to deal with such things? Any hexbears who regularly deal with this or have suggestions on how to handle such situations? Am I just fucked with dealing with assholes?
Content Warning: self-harm
So, I get sensory overload pretty easily with seemingly small auditory cues, such as whistling, intermittent humming, low frequency vibrations (like from old AC units or fluorescent light bulbs). Someone I am forced to interact with on a daily basis decided they wanted to make me squirm today by whistling off-key repeatedly, loudly, and very near to where I was working. When I asked them to stop they continued to do it, kind of like a sibling who is bored and wanting to get some entertainment by driving the other party crazy. After 20 minutes of it I was getting to the point of distress, and I asked them to please stop because it was making me uncomfortable, and their response was to try and do it more loudly. I finally went to them and talked to them directly, face to face, and all but begged them to stop because it was making me uncomfortable and it was getting disrespectful, near tears at that point, and they rolled their eyes and said "Sorry you got triggered". The reality was that I was to the point of starting to scratch myself with my nails to distract myself because I was so distraught from the noise, something that I've come to understand happens when I'm starting to dissociate. I'm ashamed to say I dug my nails in enough to draw blood and leave marks, something I haven't done in a long while. Ended up leaking a few tears, which is really embarrassing and shameful for me when I'm not alone...
I have to work with this person every day, and I can't wear headphones/ play music/ do things to block them out like I normally would. I just got this job but I'm already to the point where my mental health is being trashed after just a few weeks.
Am I SOL? Anyone have anything that could help with this, even if it's suggestions on dealing with over stimulation in a work setting as someone with autism? I keep my ND a secret; no one knows I'm on the spectrum. ...am I overreacting? 
Is this a coworker? HR is useless, but they are deathly afraid of lawsuits and bad PR. If they keep refusing to do anything to settle this matter, perhaps try contacting a lawyer who’s willing to speak on your behalf and have their presence imply a possible lawsuit.
Yes, someone in the same office. Problem is, I haven't claimed that I technically have a disability or need any accommodations in any way, which technically is in violation of my application and hiring paperwork, where I lied and said I didn't because I was desperate. I can't express how many times I've been told that I overreact to things by NTs, and it's part of why I've been so heavily masked all my life. I need money desperately right now and was grateful I got the position. I appreciate the suggestion but I'm not sure I'm competent or confident enough to talk to HR or a lawyer about someone whistling, which is generally not considered as an issue with most people, when I am masked and trying to hide the fact that I'm not normal. Sorry if that sounds defeatist.
Whether or not they know about your disabilities doesn't matter. If someone's harassing you for your reactions, it's still harassment no matter even if you were NT.
So if asking the person not to be dick doesn't help, go talk your manager or hr that this person is harassing you. No need to explain any of the potential reasons why you may be more sensitive to the harassment
No need to apologize. Corporate environments rarely teach you how to handle this outside of a 10 minute computer quiz. But like others have said, it’s still harassment regardless of condition. If you have documentation that you requested someone to stop doing something that makes you uncomfortable and the action isn’t required for their job, then they explicitly confirm that their intention is to be hostile and continue the action, that’s harassment.
Not sure if is neurodiversity related, but some people develop auditory problems due to various factors including common environmental noise, age, accident, etc. so asking someone to stop making an unpleasant noise isn’t irrational even for someone who wouldn’t understand neurodiversity. It’s no different than microwaving fish and refusing to stop when everyone confronts you.
Thank you, I'll start keeping track of things starting today. I appreciate the response
I'm sorry you're going through this and that too many people have normalized abusive behavior. It sucks you've been forced into this situation with so little options and support. Hope you can find a way to stay safe and comfortable.