Crohn's disease was tested...
I am not sure about lyme's it very well may have been tested, but I find it very unlikely that I have it. Though I have many times very short attention and am pretty depressed (suprisingly...).
For the weight part it really seems like an appetite issue. Of course the diarrhea makes it worse.
Anyway I read that steroid called anavar is used by elders with weight problems...