If you can purchase a quality whole body vibration machine, or visit a gym or studio where they use one, you can get some exercise without overexerting yourself. With whole body vibration you hold basic poses while on a vibrating platform that works your muscles. It's no-impact and many people who suffer from pain or fatigue find it relieves their symptoms. I hope that helps.
I have been ill for 6 years & have continued to lose weight. I get no exercise except slow walks. It took my a long time to realize why I was losing weight. At first I thought I was eating enough. Then I realized I was sooooo tired most of the time I wasn't bothering to eat. Too much effort. Plus I have no appetite with gut issues. Now I smoke pot to get my appetite going & I started taking Boost everyday.I'm starting to gain weight for the first time in years but I have to really work at it.
Depends on your diet.
It is possible I guess, if its getting to a point that you're skin and bones then taking vit. Min. and probiotica helps.