Hi Dread,
Sounds like a right bugger!
I noticed the post started in 2013, but I thought I'd chip in just in case it's still bothering you.
If we were to go with the somewhat expected approach of suggesting psychedelics, I think perhaps something with legs but not completely overwhelming (LSD, Mesc, Shrooms, with a strong suggestion on Mesc) and someone there to talk the issue through. Alternatively, you might even want to knock out the psyches, and go with MDMA and word. Take the Mandy, and then sit there, and write. Talk to yourself about all these issues, and write about how they make you feel, and where you think they come from. Once you are done, go back over, think about what you've written, and edit it where you think is appropriate. At the end, you should have a written account of these fears, what triggers them, what you know about them, and hopefully a better understanding of what you face.
Another way is to read into cognitive fallacies (You are not so smart is a great book to start with), and learn how to outthink the issues you face.
There's also the more classic response of valium, which you should be able to get on prescription. I normally keep a supply of valium about for psychedelic emergencies or to close off a night of stimulants, but I also used them when I encounter stress (like this month, I have a move, two mags to put together, an event to organise and a trip to US to speak, with a ton of other moving pieces to consider). If you are unfamiliar with them, while it doesn't so much as remove or resolve the problem, it definitely helps you not care, and is essential stuff if you are feeling anxious before having to go into social situations. I used to have them for anxiety attacks, but they kind of fell by the side after my dabbling with LSD and Mescaline.
The other one is simply more exercise. One of the best problem solvers I have involves a cycle, padded shorts, and a 25 mile ride on a day where it spits warm rain. You end it feeling too much like a boss to care about anything else
As for the condition itself, it sounds like a psychosis that could be attributed to numerous mental health conditions, so it'd be impossible for me to give you any sort of suggest what the underlying condition is (if there is one!).
Also, figure out how you beat it in the past, and learn how to contain it. That way, you can mentally sidestep it in the future.
Life should not be a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside in a cloud of smoke, thoroughly used up, totally worn out, and loudly proclaiming "Wow! What a Ride!”
― Hunter S. Thompson