To manage it I try to exercise every day, including occasional yoga and meditation. I refuse to take sedatives for it, or any meds, except for over-the-counter remedies for hive relief that my doctors have recommended. (BTW, did you know that taking something like Claritin along with a stomach remedy like Zantac will reduce hives discomfort?! My doctor told me that and it works!)
Anyway, I live a stressful life, which I bring upon myself with my grueling writing deadlines, set by both publishers and myself. Coupled with a day job, it's a wonder I don't scratch myself bloody. I'm doing better now. Last year the doctor gave me a stern warning about stress overload bringing about more serious ailments like stroke or heart attack. I listened and started cutting back on some activities. I also eat a lot healthier, which helps. And decided to go easy on future book contracts.
I'm also a news junkie and seeing the carnage at the Istanbul airport last night didn't help my nerves one bit. I'd also learned of the passing of a friend's spouse, so I was pretty sad about that too. I turned the TV off and went to bed early.
Yesterday I was telling a friend about something really stupid someone said to me over the weekend, and I got way more agitated than the situation called for. (FYI, making mountains out of mole hills is another sign of increased stress.) So I took a several deep breaths and tried to shake it off.
This year I plan on releasing several books, in spite of the above. The two coming out from publishers are already written, so I can relax about those. Another publisher deadline is not until later in the year and I'm already working on that book. The others have already been started and will be self-published, so if I don't make my self-imposed deadlines for those books, it's okay. It means I'm being smart enough to pull back on stress triggers in my life.

Whenever I see hateful attacks splashed across Facebook and Twitter, I wonder about the stress levels of the people writing such comments. Maybe they are lashing out at the wrong targets; taking their frustration out on strangers instead of the true source of their discomfort and anger. And maybe they brought a flame thrower to a garden party. Kind of like what I did yesterday. My reaction was a massive bomb, when all the situation with the nasty comment called for was maybe a squeak or two.
We all need to chill out. We all need to take a step or two back, weigh the situation we're reacting to, and respond appropriately.
It's difficult in these difficult times, but if more of us did that, maybe it could spread to others like warmth from a cozy fire. It might also leave us enough emotions to properly handle true tragedies, like bombings at airports, and massacres at night clubs, and slaughter at a church. These things deserve our anger and attention, not the petty stuff.