Something that I will mention about thyroid - the range of ‘normal’ is huge (0.2 - 7.0). ‘Normal’ may not necessarily be normal for you.
Don’t panic yet though - a very similar thing happened to my SIL. Turned out she was stressed out at work and wasn’t eating as much, and didn’t even realize. Not saying this is your problem, but hopefully it will turn out to be something just as trivial.
My experience with doctors has been that if an answer applies to a simple majority of people, then it clearly applies to you, and no further questions or investigating is necessary, nice to see you today, take this paper to the front desk - - EH! - EH! - Goodbye.
Maybe its lupus.
It’s never lupus. Now how do I get to be a patient of Dr. House? He can examine me anytime!
I also don’t mean to worry you, but my dad had some pretty dramatic weight loss late last year. He went to the doctor because he was worried about cancer.
The doctor assured him that it was because he was bicycling. He told my dad that people with cancer don’t eat normally and they don’t have energy. On top of that, all of my dad’s blood work came back normal.
A few months later, around Easter, they found out he had cancer (either pancreatic or liver, still not sure because it had progressed to the point that it didn’t make a difference). He had had the cancer since July of the year prior. He passed away a few months after that. Up until a few weeks before he had passed they still saw normal blood work. The doctor said that if he only had to go by the tests they had done, he would still have given my father a clean bill of health.
If you feel that something is wrong, don’t just take their word for it. Get multiple opinions if it is possible. I wish you the best of luck and hope that it is something else much less serious.
Just don’t let him stick you in the MRI machine. 
Good luck on finding out what it is. I swear, between you and olives, we’ve had enough of these medical mysteries to film a whole series of *Mystery Diagnosis *shows!
dont worry, i found it stuck to my ass and thighs … you can have it back, i really dont need it …
good luck, but from what i understand getting good regular sleep can actually improve your metabolism, so maybe that is what happened?
[trying to put a positive spin on it here…]
I am not a doctor but it seems to my non-medically trained brain that losing 17lbs in a month just by getting more sleep and nothing else is borderline out of the question, at best. I think the main reasons getting more sleep is recommended for weight loss are peripheral; it leaves you with more energy to work out, and it’s thought to ease stress and depression, which are thought to contribute to excess bodyweight. I don’t think sleep itself is a calorie-roaster of the 17lbs in a month variety.
Now that’s not to say they’re unrelated. Whatever is making you shed the pounds could also be making you tired.
I’m guessing they checked for anemia, right? Because that could make you more tired than previously. One cause of anemia can be hidden internal bleeding which can again come from a variety of causes, including cancer. I hope it is none of those things, and that you rapidly become healthy again!
It happened two times to me, both times no medical reason could be found, both times I gained weight again after 1-2 months. Both times it was a very unhappy period in my life (failed love affairs) which may have affected eating and sleeping patterns without me even noticing.
I once lost a little over eighteen pounds overnight. It was the damnedest thing. I wasn’t sick, there’s no history of diabetes in my family. Just, I went to bed weighing X, and I woke up weighing X minus 18. Everybody was as mystified as I was.
Finally we realized that the tiger had got my leg in the night.
If they didn’t check for anemia, that is a sign of a completely incompetent doctor. The cause of anemia can be more tricky, there being over 300.
Especially since Annie was quite slender to begin with. 17 lbs is probably a significant percentage of her body weight.
My dad was another one who had unexplained weight loss which turned out to be caused by cancer. (Though if it makes ya feel any better, Annie, at the same time as he lost the weight, he got insomnia instead of losing it!)
That kind of weight loss may be nothing, but it also may be a symptom of something serious. Please please continue to pursue an answer to this.
Perhaps a silly question - when was the last time you checked your scale?
Regards,
Shodan
This morning, silly! That’s how she knows she’s lost 17 pounds! 
A very good point. Periodically I have to put a known weight on mine and adjust it, as it somehow manages to drift out of calibration over time.
hey Annie-Xmas, any news?
was? Was! She’s past tense now!
What a shame.
Lovely plummage!
We need news!!11!!!
An out of calibration scale won’t make your clothes too big though.
You been under stress, Annie-Xmas?