Hi Braves, and welcome to Anxiety Zone... My name is Chuck, and I am one of the Global Moderators here on the site.
You are now a member of our community, where you will find support and advice from other members in similar situations. It's always nice to find someone else who understands, and to know you're not alone.
We have sections in the forum that address specific concerns, so feel free to post or start a new topic in the section that best fits your situation. Feel free to explore the rest of the forum. You may find the other topics helpful, and you may be able to offer advice or support to someone else.
We also have a chat room for members over the age of 18. Once you have made three meaningful posts, you will be allowed access to the chat room.
Braves, you are describing a most classic pattern of a anxiety/depressive disorder. I have never found a name for it, but I call it "the light-switch effect". It happened to me again, just last night. I was sitting in my favorite easy chair, watching a little TV, and out of nowhere it was like someone hit that light-switch and this overwhelming feeling of a deep dark depressive thought entered my mind. When you are sensitized, these thoughts can come out of nowhere, or a simple thought like having one dirty fork in the kitchen sink can trigger them.
You mentioned that you have seen four doctors so far. I saw six before I saw the right one, and that right on was a psychiatrist, and boy am I glad I found her. She gave me a diagnosis, put me on anti-depressant therapy, and put together a treatment plan tailored just for me. That plan included seeing a therapist that specialized in anxiety disorders. By-the-way, anxiety and depression often run hand-in-hand; they can be like Siamese twins.
So, you are not alone, Braves. You will find plenty of company on the site, and that includes me.
Good to have you here. The very best to you, Braves!... Chuck