Try treating your sensory overload like a migraine (there are a few similarities).
If you're in the US, go to your local Walgreens and get yourself some earplugs and a bottle of Hyland's Migraine Headache Relief tablets (it's a small box that should be with the aspirin and tylenol and stuff). Go home, take two to four of the tablets and pop in the earplugs. Then grab a folded, slightly moist washcloth. Darken and quieten your bedroom as much as you can. Lie down on the bed or on the floor, comfortably on your back, with your head and neck supported by a comfty pillow, your spine straight and relaxed and your arms and legs relaxed (like the "dead" pose in yoga if you know that). Place the washcloth over your eyes, relax all your muscles (especially our facial muscles), breath deeply and calmly and try to clear you head. Then imagine you can see all the tension and anxiety circulating through you. In your mind, visualize it as a blue light that you can mentally direct to your finger and toes where it evaporates and leaves you body. If you start to doze off, then just doze off. Give yourself at least 3O minutes, but an hour would be better.
Yeah, sounds little crazy but it helps me.
If this is something that happens often to you, you should try signing up for a yoga relaxation techniques class. Tell teh instructor exactly why you are taking the class - to cope with sensory overload. They may call it something else, but whatever. It's the same deal. You don't have to buy into their yoga jargon if you don't wish to. But they will teach you techniques that you can use as a long-term preventative for sensory overloads as well as other "quickie" technique to help you get through the day when you don't have time to lock yourself up in a dark, quiet room for an hour.