Well, first, long or short postings . . . it doesn't matter . . .
To kind of answer your questions . . . I do not find it unusual that you are losing weight because you are not eating . . . during episodes of depression, food is the last thing on my mind and during episodes of anxiety the thought of food, well, trust me, it's not a pretty sight . . ..
The good thing and there are a couple of good things . . . first, you had a lot of tests done and physically you are fine; you do not feel weak, etc. and the other symptoms (gas, etc.) are not unusual because your brain and your gut are connected . . . the GI doc explained it to me and it has to do with the nerve system that connects throughout your body and the GI tract and the brain share some of the transit patterns (oh joy, no?) . . .
Now, you do need to invoke some management techniques to move away from focusing on the same thought non-stop because that is keeping you embedded in your depression/anxiety cycle in my opinion. However, the other good thing is that with your loss of weight, you seem to be able to do flexes . . . super . . .this leads me to think (and just think) that the weight loss has had a really big positive effect . . . perhaps your back issues were from weight . . . .what I would suggest is the following (1) perhaps a visit to your GP and ask for a diet that will help you to continue to lose weight --- a proper diet with sufficient fiber will help with some of your GI issues but if you are not used to fiber, start off small and build up and drink plenty of water; (2) if possible, a visit to a professional to help you manage your fixation on your thoughts and guide you with additional management techniques; and (3) a bit of a celebration, AnxietyJoe . . . the weight loss may have been a concern but it is actually a positive thing that you can now manage with a good diet and exercise taking small steps to larger ones and it has led to a decrease in back pain . . .
Just to answer your question . . .I have experienced the same . . . . I lost about 70 pounds in about 2 months when my Mom was hospitalized with cancer . . . I could not eat or sleep and I would drink 2-3 cans of Ensure a day as the total amount of intake of food . . . . eventually, when I started to eat normally, the weight loss leveled off. When I began dealing with my depression and anxiety through diet, exercise, and meditation (nothing radical) then I began to feel much better physically and mentally . . . .you need to work your way through this episode on your own terms but a little professional help might go a long way . . . .glad to hear that your back pain is gone as I have had it because of anxiety and it is really a b*&^% . . . take care, KC