yoel- welcome aboard!!
first of all kudos to you for putting you thoughts into writting on this forum. your words are inspiring, keep up the good work. as you know life is challenging, yet you seem to be doing a wonderful job at it.
i really never fasted until recently, this is after about 15 years of trying to perfect my basal so that i shouldn’d go too high and dehydrate nor too low so that i should pass out.
(this yr tisha baav i didn’t make it) many times on yom kippur i have eaten and people have seen me. i usually tell them that it’s medical and i have to eat (even though I look perfectly “healthy”). (there is somebody where I daven who is hooked up on Iv the whole 26 hours of yom kippur every year). What i try to do, (if I have to eat) is to eat less that a kezayis, an olive size, (28grams) evey nine minutes (usually i wait a little longer). maybe ask the rav if you can use his room for privacy. remember that if you or me or anyone has to eat- it is a MITZVAH and that is our way of serving Hashem.
you are doing great and keep it up!