I started eating less fat (and no biscuits or chocolate) at the beginning of September, in a bid to lower my cholesterol levels and get healthy....and now (though I panicked about 3 weeks ago and started eating a lot more carbs and a fair bit more fat!) I am still slowly losing weight, looking scrawny, and not sure why 
I did go to GP, who ordered bloods and an abdominal/gynae u/s because of my age and medical history (hepatits years ago, but am sure its not related) - the u/s was fine, though obviously not a very fine-tuned test, and get bloods back on monday.
I have been more anxious than usual, for a variety of reasons, but could that account for my inability to put weight back on? Really? dh says I'm worrying over nothing...but.....