This post is particularly directed at new writers. You have worked long and hard to finish a work of some sort ... article, opinion piece, short story, novel, you name it. Your dream has come true and some newspaper, magazine, publisher has picked it up. Your work hits the presses. It is a very exciting time. You are walking on clouds and loving writing more than ever.
Then it happens. Your baby sent out for readers to enjoy meets the critic. Someone out there doesn't like some aspect of what you have done. They are letting you ... or the world ... know about it. Now, here's what to do. Sit down, take deep breaths, and try to relax. Try not to take it personally. Let the feelings of pain, panic, and grief wash over you and know, really know, that you are not alone. Everyone who has ever written, who has ever performed, who has ever done anything for the public has suffered as you are suffering. You are not alone. Do NOT hurt yourself over this. The pain will diminish in time and you will be stronger for it. Really. You will learn how to cope with this. I can tell you quite honestly, the first time my first book received a bad comment, it made me sick. I went home and to bed. But, I got over it.
Here's what you can do. Once the emotional pain has subsided, go back to the critic's message and try to examine it for what it is and who sent it. Is there anything there that is useful? Is the critic a knowledgable pro from whom you can really learn? Had you overlooked something in the writing, something missed by you, your editor (it happens, nobody can know everything and we're all human), anyone else involved in the process? If so, you can fix it later or file it for future use in other work. This will make your writing better and your skin thicker for future critics. If there is no merit to the complaint, forget about it. We live in an age of trolls, those strange creatures compelled to comment on things they know nothing about and who wish to do so with great emotion (weird). You may need to get a friend who knows your work to help you see if there is any merit to the critique the first time through.
In a number of cases, you may discover the critic is just plain wrong. Or you may find you are living in a period where critics are compelled to find something wrong with everything and make mention of it. You'll need to decide if the critique has merit and what you should do about it. Also, remember this. You are a person of worth and talent. You are worth more than whatever the price of that work you created cost the reader and that price does not give any reader, any critic unlimited access to you and your life. You don't come that cheap. Good luck with your future writing. You'll get through this. We all do.
For some sound and time tested advice on dealing with trolls, see: http://jsbrookspresents.blogspot.com/2015/01/before-quibbling-or-trolling-listen-to.html