Just found out my 14 year old girl has diabetes. What now?

Hi. We just got the news today. Our litter robot was showing that she was going to the litter box way more often than usual. I also noticed her drinking more water than normal. Anyway, the vet started her on Bexacat and after reading so many horror stories, I'm just stressed and scared. We have a follow up appointment Wednesday. Any advice is appreciated.