I did water omly 40 days fast about 9 years ago.
I am 46 now and generally O.K. Be very careful
when you come back eating. What I think is that my
water fast did not eliminate some of the digestion problems
I had. But for some time I am doing liver and bowel
cleansing and see much improved some of my symptoms.
You probably got your sinus problems from gallstones
forming while you are fasting. Gallstones are often the cause of
sinusities. I am Not a specialist, but I tried quite a fiew things myself.
Hoping this might give you some other opinion.
Sometime you might push very hard, but it may not be the right way.