I never had a TGA but I can certainly speak to migraine auras. My presentations are unlike yours but auras nonetheless. And those of us who are unfortunately suffering from migraines could probably tell you many different symptoms. No 2 folks are alike.
There is the yawning and so-called "phantom" odors no one else in your company smells. The odor could be anything at all from cigarette smoke to cow manure to rotten fish (the list goes on). And there is "allodynia"...scalp sensitivity, you can barely touch your head. And the vision changes...once I saw 2 perfectly round blue-sky circles in front of my eyes. The blue was actually pretty as odd as that sounds. And then there are the "waves" in the corners of my eyes, the first time it happened I thought I was having a stroke - just to name 2. All lasting about 30 minutes or more. And when driving my husband can not make U turns...I instantly get nausea/migraine. And thank goodness for migraine sunglasses which I wear over my regular eyeglasses when watching TV. The glare unbearable. Do you have a migraine ice cap? Also handy. Of course, I am on medication - the CGRPs as I can not take the triptans because of heart disease. Even with medication, the auras can and do appear. My sense is you could be on better medication than the nortriptyline and need preventative medication too - not just for an acute attack. Over the past 5 years more migraine medications have appeared on the market than the last 20. But changing medications is common. One works for months and suddenly does not - so a change up called for. And then this is all repeated again and again. The life of a migraine sufferer. I even have a neuromodulating device for prevention which worked great for months. Now? Not so much. And brain fog is a given along with dizziness. I am assuming you had a CT scan/MRI of the brain? Also, I found not all neurologists are headache specialists. Maybe a physician change is in order? The National Headache Foundation and the World Migraine Summit are 2 good resources. I truly feel you could be receiving better care and more "up to date" care. But of course - your call here, whatever works for you. The very best of luck!
Most folks don't know migraine is a true neurological disorder not simply a "headache".