To answer everyone's questions at once: the reason I feel as though I'm suffocating is that I've been breathing quickly and shallowly my entire life. This is why it's hyperventilation occulta - the hyperventilating isn't obvious even to me. It's not like the kind of hyperventilating when you panic, so breathing into a paper bag isn't going to help - it's hyperventilating over months and years, not minutes. I have to completely retrain my muscles and/or lungs to do something different.
The reason for my physical fatigue and muscle weakness is that for months and months now my muscles have been not getting enough oxygen, thus respiring anaerobically, and thus building up an excess of lactic acid. Most people are familiar with lactic acid buildup from exercising - well, this is like that on a grand scale. You get into a pattern whereby you breathe incorrectly and start to feel pain because of it, and the pain stresses your body and makes you continue to hyperventilate, and this spirals and spirals until it's completely out of control. I was rather unconvinced by the diagnosis because it seemed to be trivialising the problem, but the resources I've found about chronic hyperventilation syndrome suggest that yes, it's a very real problem, and if it goes on for long enough it can be as disabling as the problems I've had.
My doctor was quite pleased to make the diagnosis because he's been puzzled for years (since I've been seeing him) as to the cause of my joint pain and stiffness, when various physical tests have come back negative. When you are chronically ill, you go to see the doctor every month or so for them to try tests and see how different drugs have worked, and each time you only talk about the symptoms which are most troubling at that time. Over a many-year illness, all the symptoms are there in your medical notes, but in a 15 minute appointment, the doctor doesn't have time to go back through it - 8 or 10 or 13 years of illness, seeing the doctor every month - that's a hell of a lot of notes! So it wasn't until I typed all the symptoms out together that it was obvious. Apparently.
He said it explained 90% of my symptoms - basically everything except me always having a cold and the allergy stuff. Well, poking about online, I discover that when you are in this pattern of crappy respiration, the histamine level in your blood rises. Now, most allergy medicines are anti-histamines - I'm not amazingly sure what a histamine is, but I know it's implicated in allergies. So that could be connected too. Also, me always having a cold - if I'm breathing through my mouth too much, I'll be taking in a lot more germs, because the mouth is much less good at filtering air than the nose. Hrm. The other thing that's interesting is that I have become more and more ill since I've been working for the market research place. Now, if all my problems, or 90% of them, are linked to my breathing, being on the phone all day could explain how they've got worse and worse - because when you're talking constantly, you do a lot more shallow mouth breathing. I know a couple of times when I've been at work, especially recently, I've found myself having to take a toilet break just to go somewhere and breathe slowly for a couple of minutes because I've felt dizzy from lack of oxygen, and I get through Olbas inhalers at a ridiculous rate because talking too much with a blocked-up nose makes me nauseous.
The other other thing is that in some of the articles I've read about chronic fatigue syndrome which have talked about it actually being a catch-all term for a huge variety of problems, chronic hyperventilation has been suggested as causing some small percentage of CFS cases. I completely ignored that when I was reading them before because I thought I knew what hyperventilating was and didn't think it had anything to do with me. Hrm.
I haven't been referred to anyone - Kingston has fuck all money and a huge waiting list for anything, it seems. I did specifically ask my doctor about physiotherapy, but he just gave me a printout about "yogic breathing". That probably sounds quite callous on the part of my doctor, but it didn't come across that way to me - I was just in shock at what I'd just been told (you mean, I've been disabled to this extent by my breathing??), and not at all convinced by the diagnosis. If I had've realised that this isn't a new problem, I've always breathed this way, then I might have pushed a bit harder. As it is, I'm not sure that seeing an ordinary physiotherapist would be any good. There are asthma clinics around, but when I inquired about them in my teens, was told they were just to teach you how to use your inhaler properly. Well, that's not very difficult, is it? The instructions even have photographs! Teaching breathing techniques was probably a bit new age for the NHS in the early 90s. I don't know quite what would be encompassed by them now.
I have ordered this book - if it doesn't go into enough detail or I still have problems, I'll ring up the Butenko people and find out how much their specialist "teaching asthmatics not to hyperventilate" courses actually cost. Going to see how this goes, and take the rest of my month off work, because going back to a job where I don't breathe properly for 4 hours at a time would be a very bad idea just now, and I'm chronically behind on my degree again because I've been ill for a large number of weeks.