Hi Sarah
Sorry to hear you've been feeling so bad. As suggested above have you changed your insulin, diet, alcohol intake or physical exercise recently?
Also, you say you've only ever had two hypos before now. Did you mean two hypos ever or two hypos as serious as this one? If you have only ever had two I would suggest that POSSIBLY your BGs have been running a bit too high all this time (otherwise you have the best diabetic control I've ever heard of!). Although obviously hypos are not a good thing, they do tend to happen to everyone now and again, particularly if you have good or tight control, because you're always aiming to be at the lower range of the normal range of blood glucose readings. That means that a relatively small amount of extra insulin or miscalculation in dose can result in you going too low. If you never have them, it could suggest that you tend to sit at the higher end of the range naturally. This is just conjecture, though, and I'd be interested to hear your view!
Do you test regularly? Can you let us know your last HBA1C result?
Do you have access to a proper Diabetic Specialist Nurse at a diabetes clinic (ie not a self-style practice nurse at the GPs?). A DSN may be able to help you out, too, and can sometimes have more time or be more sympathetic than doctors...
Good luck!
LJ