I'm allergic to polyester and most anything made of plastic. I get painful open sores, and hideously itchy. It is difficult to find clothes at best.
Plastic is snuck in more shit than you'd think. Often unlabelled. More than one pair of pants/shorts I've had to ditch/edit because the pockets were polyester or nylon in a "100% cotton" garment. Drawstrings are bad for this, too. And waistbands.
Seems to be weirdly common to be adverse to plastic-based fabrics in autistic communities.
I most often wear:
cotton/linen/canvas/denim
rayon/bamboo (plant based, do need to be a bit careful because people fake it, very loose "swishy" fabric)
hemp
real leather ("vegan leather" is literally plastic and i will fight people greenwashing calling it "vegan" and not the awful pleather it is.) (very difficult to find coats without nylon linings though.)
I have autism and bipolar 1.
Autism does not have pills.
Circumstances of your birth have no causation to autism. Neither to circumstances of your life. All sorts of people have autism from all walks of life.
A reason to research and understand one's own autism is to recognize what in your life overwhelms you, and how to structure your life in a way that is comfortable and functional to you, without a judgemental neurotypical lens. To embrace who you are, rather than try to force yourself to be something you are not.
You can seek a diagnosis if you wish, but I can't tell you if it'd give you what you're looking for.
I learned about my conditions through following various mental health communities for years and seeing what had commonalities with me through the fun lens of dank memes. I also learned a lot about medications, warning signs in therapists, and I learned what mental health conditions I don't have. Can't say if that'd work for everyone, either, but I did learn a lot more from the communities directly rather than reading the clinical book definitions.