Without dismissing your Autism in any way as I appreciate labels like this have their use and people can suffer from "it" in varying degrees. However aware many people with or without autism label have the same anxieties about new situations, busy places or even just the general madness of todays society, including the noise created by anti-social media and the insesent rubbish from smart phones and instacrap etc.
My advice would be plenty of meditation, join calm group with confidence calm and humble people in them, and take position of watcher where ever you can, watching the choas unfold and seeing the good within that chaos. Remember religios or not we are all a creation of the one, god or whatever you want to call it, and we all at our core are one and want to be good. So the chaos you find and the over stimulation is something everyone probably notices to some degree, but with the use of ego, resiliance, or just pure ignorance many of us get through but still suffer.
Change is always hard, but much like moving into a new move in Yoga it will hurt at first, but its the more we stretch and move the more we strngthen and soften the hardness of the bumps and aches, and eventually we become able to move with the wind rather than battle it.,
Read some spirituality books too, Ekhart Tolle is a good writer for this - made a big difference for me.
Good luck my freind.