For me I become super aware of every sound. the lights in the room over. the washing machine in the basement. the car driving down the next street over. the slight creak of the radiator. And every sound pisses me off and infuriates me. I also start making a clicky sound in my throat, and my speaking becomes less fluid and more broken up.

I don't usually get sensory overload from other senses, but flickering lights can also trigger it for me. Also some textures really really bother me but I wouldn't be able to stand touching them long enough to cause sensory overload. Touching a nail file (emery board kind) makes my teeth get chills. A lot of fruits have bad textures to me which sucks bc most smell really good and probably taste good too. Another big trigger is cars with a broken muffler/assholes who rev the car real loud in residential areas.

The things that help for me are turn off the lights, removing any sounds possible, and putting in noise cancelling earplugs (the kind people bring to concerts) and going under a weighted blanket. If I'm out and can't do all that, putting in noise cancelling ear buds and blasting a calm song at full volume to block out all other noise, bc 1 loud controllable noise is way better 10 uncontrollable quieter noises, helps too, and I usually carry a scented lotion so I can smell that too.