Hi Jayjay,
As you're probably gathering we all go through tough patches with diabetes, it can be under great control for years and then we hit a sticky patch and we're back to square one and there isn't a reason that we can fathom.
Your DSN is a great first port of call, the other suggestion made, Diabetes UK careline is where I turned, they answered my questions straight, factually and sympathetically. Well worth the call. And sometimes worth your partner calling, if for no other reason than to be reassured its nothing other than your diabetes.
They [Diabetes UK] made me realise I wasn't alone in feeling down, fighting this battle alone and now we're all here online. Some with far more knowledge of the technical aspects of the condition, others, just with an ear and a voice of sympathy to say unlike those without diabetes who don't see or know how it feels to have this condition.
I think its great that we can release our frustrations amongst others, new and old hands with the same condition.
Hope you soon get over this hurdle and are soon enjoying life again.