I am sorry to hear about the difficulties that you are having with anxiety. You are certainly not alone.
My problems with anxiety (GAD)/panic attacks/depression/intrusive thoughts started some four years ago. I was fortunate to find an excellent psychiatrist that is in charge of my mental health care. A psychiatrist is a medical doctor, and therefore can provide you with a diagnosis and also prescribe medication if necessary. I have been on an anti-depressant for some four years now, and recently had to start a new one, Celexa, because the Remeron I was on stopped working for me. I have been on 20 mg of Celexa for some 6-7 weeks now, and am doing so much better. I will also be seeing a psychologist at the end of the month, to begin cognitive behavior therapy (CBT). I also have a regular therapist through my work, that I can see when I want to.
I know that you mentioned that you have been to your regular doctor, on more than one occasion, but that you feel they haven't done much for you. I would highly suggest that you consider seeing a specialist is the area of mental health, such as I am doing. There are also many things you can do on your own. These include exercise, getting proper sleep, meditating/mindfulness, keep oneself hydrated (drinking plenty of water), eating small, frequent, healthy meals, and reading self help books, to name a few.
There is no reason for you to suffer, as there is so much that can be done for conditions related to anxiety. The very best to you, Oasis!... Chuck