"Overstimulation, overarousal, and the resultiing stress are the downside of being highly sensitive. All HSPs develop ways of coping with this tendency to reach overarousal more easily than others. Your first task is to take notice of what you already do to handle overarousal by making a list of your especially brilliant coping strategies.

Purely as examples to warm you to the subject, here are five of my own.
1. If I'm being overstimulated by a situation, I leave! I've learned I'm not irreplaceable. I can always apologize later.
2. I try not to say yes to a request for my time without reflecting on it--saying, "Let me get back to you on that."
3. I block off rest time in my date book, and set aside even more time after a day that will be highly stimulating, and keep that sacred.
4. I take a walk when things get intense, preferably in the woods or near water.
5. I take ten breaths from the abdomen."

~Elaine Aron, "The Highly Sensitive Person's Workbook"

My own list (in addition to doing the above as much as possible) for coping as an HSP and someone with fibromyalgia:

1. I wear earplugs whenever the noise around me feels too loud (like when people are banging on the walls). I can still hear what people are saying if they're talking to me with the earplugs in and I can still watch movies in the theaters. I wear earplugs to sleep every night too. It'd be nice if I didn't have to wear earplugs because they're uncomfortable but wearing them definitely helps when things are painfully loud.

2. I turn the phone off or change the settings to "soft" when I'm feeling extra sensitive because the ringtone will startle me (exaggerated startle reflex) during these times. I also turn the phone off or simply not answer when I know talking to people will take too much energy. I can always call people back when I'm feeling better and can focus on our conversation.

3. I close the curtains and blinds and go to bed (just lay down)when I am extremely tired or have a migraine.

4. Sometimes overstimulation gives me a fever (like getting too much sun or being with rowdy people for a long time), so I eat a popsicle or ice cream to cool down. Yum.

5. I set my computer to chime every half an hour to remind me to stretch and release tension.

6. I take a warm bath to relax, sometimes with the lights off.

7. I pet my rabbits. They are great at calming me down.

8. I get a hug from Lyle, if he's available ;)

9. I read or do puzzles or doodle in a quiet place.

10. I go for a walk.

Pretty much, I need to get away from the aggrevating stimuli first to take refuge somewhere quiet (and may be dark), then do something calming. Rabbits like to burrow ;)