Advice specifically on high functioning anxiety

[Lastnamefirst]

Would be grateful for any help. I suffer with high functioning anxiety (I’m aware this is not a diagnosis technically speaking, but I literally fit the description absolutely perfectly). I’ve never taken any time off work but sometimes the anxiety can be debilitating and I can feel as if I can barely breathe for long periods of time. I find it very difficult to cope with error (or the possibility or prospect of error) and I’m incredibly self-critical. I’m getting to the stage now where it just exhausts me and my productivity is low.

Has anyone got any advice – particular books, online programs or even particular therapists (London)?

Forgot to say that mindfulness meditation is very helpful, lots of free meditations here www.freemindfulness.org/download
The five minute tension release or breathing space ones by Vidyamala Burch are great to start with.

I think of if on a scale, I can operate at 4 or 5 and need a degree of stress or I get nothing done, but when it tips into overwhelm I know I have to pull back. I find having something short term to look forward to helps and trying to identify and deal with the triggering situation. Also yoga I developed a practise in my 20s and it is fundamentally the best thing for my anxiety but you have to do it weekly.