Health issues making me homesick

Hey

Im supposed to stay for another 1,5years, currently at the 6month mark. Honestly i had only been dealing with light homesickness at the 1 month mark and everything was going well. But for the past two months ive gotten the flu twice and my stomach has been in pieces aswell. Im pretty sure its due to dietal changes. Being from Denmark im used to having ALOT of fiber. I know its ofc possible to consume fiber in Japan aswell, but it takes much more effort in comparison to Denmark where the bread is packed with it. These things are screwing my daily life completely, with me having to cancel plans every other day and having called in sick 3 times this month. Has anyone dealt with simmilar issues, and have any advice?