What can be done about Enlarged Vestibules?

About a year ago I was diagnosed with enlarged vestibules (thankfully not EVA), lateral semicircular canals, and vestibular dysplasia. This is what causes me to get car sick, however, it's been getting worse as I've gotten older. Between my severe stomach issues that arose 3 year ago and this condition feeding each other while I'm in a car, travel is nearly impossible, even for 20 minutes, without needing no less than 48 hours to fully recover and no less than an hour being still at location before trying to go back. My stomach is so easily upset and medicine has had such large side effects, I can't say I think something like Benadryl or Dramamine would be a wise decision and that leaves me questioning what to do, as it's impairing my ability to get tests I need to solve my other issue.

I hope someone might know more than I do about this diagnosis that could give me some advice.