Hi Maine, welcome to the forum.
Antibiotics will definitely make things worse, not better. You may find it easier to transition from the diet you’re on to the strict forum diet. I had what I considered a very healthy diet before going on the forum diet, but I still found it helpful to first slowly eliminate certain foods I shouldn’t be eating while following the strict diet.
I would check out the protocol, which will answer most of your questions. It specifically lists when you should introduce specific things, including vitamins, antifungals and probiotics. https://www.thecandidadiet.com/forum/yaf_postst1334_The-Protocol–Able900-and-Raster.aspx
For the strict forum diet that many of us follow, you can message Able900.