I am happy to announce that I have reached a diagnosis for my condition - I am officially a cyberchondriac!!!
I've felt increasingly anxious that I actually had some sort of nasty medical condition: in fact that's been on my mind last thing at night as I've drifted off to sleep----unsurprisingly, I've been waking up sweaty and tachycardic (see! I even know the technical jargon!) with a dull ache that seems to be centred on the caecum (ha!). various unpleasant thoughts drift through my head, mostly to do with incurable conditions, not living to see the kids grow up etc. etc.
Ironically, it was whilst surfing the web to identify the cause of the latest symptom that I came across the Wikipedia article on hypochondriasis and - blow me - it described me to a tee!
'....an excessive preoccupation or worry about having a serious illness' Check!
'....so afraid of any reminder of illness that they will avoid medical professionals for a seemingly minor problem' Check!
'....some others live in despair and depression, certain that they have a life-threatening disease and no physician can help them, considering the disease as a punishment for past misdeeds' Check!
'Common symptoms include headaches; abdominal, back, joint, rectal, or urinary pain; nausea; itching; diarrhea; dizziness; or balance problems.' Yep...had most of those!
Apparently, the internet has spawned its own version of hypochondria: cyberchondria, where the individual prone to such health fears trawls the web and becomes convinced that they have something awful, cancer and MS being favourite self-diagnoses. (Check!) However----
'Patients with hypochondriasis often are not aware that depression and anxiety produce their own physical symptoms that might be mistaken for signs of a serious medical disease..... Intense anxiety is associated with rapid heart beat, palpitations, sweating, muscle tension, stomach discomfort, and numbness or tingling in certain parts of the body (hands, forehead, etc.)' ...Errr...that's me....!
It's part of a continuum that runs from depression and what my husband terms Too Much Time To Think.
I guess I am at the latter end of this rather sad spectrum. Another clue as to my 'problem' is that 'it' (as predicted by the article and others related to the 'condition') 'improves' immensely with physical exercise (which, I suppose releases 'happy' hormones) and goes completely unnoticed if I am involved wholeheartedly in some project, meeting or converation. Only to return during the night, or when I find myself on my own. Sometimes, though, this obsession threatens to rob me of my day-to-day happiness, rendering me tetchy and self-absorbed.
Knowing what the problem is is an immense relief actually: I shall definitely make an extra effort to do something positive to relax...maybe renew my interest in the gym, which always makes me feel better after I've been.
My medical dictionary (another dead giveaway for a hypochondriac) rather amusingly compares the difference between hypochondria, malingering and hysteria:
'The malingerer may say he has a headache when he has none, in order to evade work or responsibility; the hysteric does something similar at an unconscious level and gets a real headache without physical cause; the hypochondriac spends a happy day trying new remedies for a headache that might come on.' Or, in my experience, feeling utterly wretched and convinced that death is imminent.
So it's all in the mind, then. But as the article notes: 'A simple suggestion of mental illness can often trigger one with hypochondria to obsess over the possibility.'
Dammit---I knew I was ill!!!
The sudden death of 'the King of Pop' at fifty has been for me yet another unwelcome intimation of mortality. This, plus the recent passing of an old friend and my own confrontation with the (happily unfounded) possibility of illness, has had the unpleasant effect of bringing me up short to look at the briefness of life in an uncomfortable, clear-eyed way. And I don't like it much. I am well aware that I am growing ever older - I'm showing the signs of age that we all do: loss of skin tone, grey hairs, excess weight, age spots (sounds lovely, doesn't it?). But more uncomfortably, I've become pathetically obsessed that every little ache or pain or cough is an ominous portent of Something A Lot More Serious, and that really, really bugs the hell out of me, that little old granny of twittering caution and alarm. I've always been what you might call 'insouciant' (some might say cavalier) about my health and illness in general, not giving much thought to what I've taken into my body. And now it all seems to be coming back to haunt me, all unwilling, in the dead of the night - hypochondria - big style. I lie there awake and uncomfortable and fret. Dawn arrives, and I haven't been back to sleep, so I start the day irritable and lethargic. I'm restless but unmotivated, bored with the quotidien but incapable of showing initiative. 
