I don't think your weight loss is 'unexplained' at all. Anxiety causes weight loss or weight gain depending on the person. If I get freaky, I can lose 3 pounds over night. Sometimes I will joke with my husband that I need a good anxiety freak out because I need to lose 10 pounds. Obviously when I have been in those freak outs, I am miserable. so definitely a HARD way to lose weight. Back in '96 after the birth of my 3rd child, I lost the 30 pounds I had gained plus another 10 or 15 in two months time. It was because I was an anxietal wreck. The other symptoms you are talking about also go hand in hand with anxiety/depression.
Obviously, having a visit with the doc should be done, at least, annually.. But, I am thinkin' the loss of appetite due to health anxiety is going to be the cause and not some dire reason like cancer..