I wish I had an answer for you. Vertigo is my absolute least favorite symptom. So miserable!
Do you mean you are seeing a holistic doctor? A homeopath uses homeopathy, not herbalism, and homeopaths usually aren't doctors. I'm not trying to nitpick here, I promise, just trying to get a sense of whether your treatment is homeopathic or herbal. I had some strong vertigo as a result of homeopathic treatment once, which is why I ask.
Second, it's normal to feel fine or even a little better for two weeks and then have a herx begin. Your body took a while to get overloaded, and now you are at that point where the endotoxins of the things you are killing are piling up (and poisoning you) faster than your system can process them out. Either slow down your treatment or increase whatever you do to detox. There are lots of posts about
detox if you need ideas, but some who are very sensitive just have to decrease their antimicrobials for a while.
I agree that flying can change the fluids and crystals in the inner ear and cause vertigo. (Major changes in barometric pressure can do this, too, for sensitive folks.) My mom gets lots of inner ear issues and migraines from air travel, as do I, although not vertigo.
Have you tried the Epley maneuver or the other physical therapy tricks for vertigo? There are videos on YouTube and other online resources. If you are having ear pressure in addition, then try hot compresses on the ears. I also recommend self-lymphatic massage of the neck: https://www.youtube.com/watch?v=QA-wi0d7-Ro I hope one of those things helps.
Essential oils for dizziness can help, as can acupressure points, and the acupressure bracelets SeaBands can prevent nausea.
I have only gotten vertigo from herxing. It's horrible. But I do get lots of other types of dizziness. I sort of hate that I know the differences between different types of proprioception issues....
Mold is always good to look into, but it seems like you would have had these issues before you left as well if your apartment were the problem.
Wishing you relief and steadiness!