Devin, very interesting to read about similarities to your what you experience -- thank you for explaining situations that are difficult for you and how they feel. The sensory overload makes life very challenging, I find myself avoiding more social situations as loud noises can trigger me to startle and scream out. Grocery guy drops at box at Safeway, I'll gasp & what feels like a scream comes out. I'm in the car and a noisy Harley cruises by, I'll startle and scream out. Last week I braved dinner out to a quiet restaurant, but getting to the dining room involved going through the bar, which had a very noisy ice machine -- I walked by quickly and got as far away as I could from that thing.
I'm predisposed to reacting to sudden noises just about all the time -- some days are better than others, but about half the time I'm extremely sensitive to noises. Nights are a different sort of challenge -- when the house is quiet, normal night-time house creaks can trigger a startle, even when I'm asleep. One thing I've found helps at night is to sleep with a white noise machine. Earplugs can help but sometimes they block out too much, for example if the cat jumps up to the bed, she usually announces her intention with a meow -- if I have earplugs in and can't hear her coming, it can lead to a huge startle when she jumps up!
I used to have severe headaches which the startles made worse, those are now much better I think thanks to a daily low dose of Inderal. I'm also taking Lamictal, the hope is that acts like a "surge suppressor" for sensory inputs, but the effects aren't immediate so that med is likely a long term bet.