Have you tried a whole-foods plant-based diet? It has been shown to be effective in treating and in some cases even reversing digestive issues:

https://nutritionfacts.org/2012/09/13/dietary-treatment-for-...

http://www.onegreenplanet.org/natural-health/vegan-health/ib...

Other than that, since you work from home, maybe you could see if polyphasic sleep works for you. I haven't tried it myself, but I've heard good results from others.

https://www.polyphasicsociety.com/polyphasic-sleep/beginners...

I would also suggest getting your bloodwork done to rule out any hormonal issues or nutritional deficiencies that could cause or exacerbate your fatigue, if you haven't already. Taking B12 and Vitamin D supplements might also help.

Ultimately, I don't think you're as unproductive as you think you are, but it's always shitty to feel like you're not reaching your full potential. Be aware of the symptoms and consequences of over/underworking (burnout/boreout). Good luck!