Hello~It sounds like Meniere disease to me as well. One suggestion, since all your tests are coming back "normal", I would see a chiropractor, you could have some misplaced vertebrae in your neck pinching some nerves, this will DEFINITELY cause dizziness and ringing in ears.
Oh my gosh, what a nightmare for you. I've had inner ear tube dysfunction (Eustachian tube dysfunction) with dizziness and vertigo as the result. It was truly horrible and I had great anxiety that another 'attack' was going to start! I relate to what you are going through. For my issue, I was desperate to figure it out. Have you discussed Meniere's disease? Something to look into. I also tried and with some success until I got over the hump-- taking psudophedrine. This is something you have to now ask a pharmacist for. It's OTC, no script needed, but a sought after ingredient for those cooking their own drugs. Sigh. But it used to be in every day products like coadvil, etc. They just monitor how much you buy and I think limit it. I only have bought one sleeve in all this time. But it DOES help with the inner ear issues of dizziness. REverse ear pops helped me as well-- hold nose, blow and ears will pop.
But I have no idea if this is your source of dizziness/vertigo. But do look into Meniere's disease. Let mek now what you think.