Hi everyone! There's something very mysterious going on with my body, and really need some ideas on what it might be and how to tackle it.

As previously posted in previous threads, I've had this Buddha Belly thing going on. I'm thin build but my stomach looks 6-7 months pregnant dispite ANYTHING I do. Doctors can't agree on what it is, but they agree it is very unusual. One said "fluid retention" and another said "insulin resistance".

I started thyroid meds (synthroid) 7 weeks ago, and I did lose some fluid retention, and my appetite is suppressed thanks to the meds. And I've been low carbing it for about a year, and even cut way down on my 2 glasses of wine (which you guys mentioned might be my problem).

But...here's the question and mystery part. My stomach changes from soft and appearing like it's "going down", to rock hard, huge, bloated....all in the matter of one day! Usually in the morning I'm flatter/soft, then no matter what I eat or don't eat, by evening I'm bloated, very hard and full in the stomach. Is this normal? If not, any ideas what could be wrong? Any way of telling the difference between fat, fluid, or even gas?

So I tried cutting down more on carbs, tried drinking more water in case it was fluid retention, etc. Just when I think it's working, I bloat up like a whale again!
I even got desperate and ate only salads for a couple days...I bloated up after eating the salad! Yesterday I was in a hurry, no time for a decent lunch, so grabbed a can of soup. Two hours later I was SO sick with indegestion I had to take Pepto Bismal and hit the bed for a couple hours....and my stomach stayed hard/bloated the rest of the day. From the ingrediants (read them after the fact), it was wedding soup and had soy in it and a bunch of processed junk.
That's making me think I'm having some stomach inflamation (not sure what?), that's causing me to store fluid or gas or something. ANY IDEAS??? Or is it normal to change like that over the course of a day? Thanks for any help.