Brain fog is real. Anyone else?

Ended up in the ER last night. Sudden loss of peripheral vision, my left hand went numb, and half my face felt frozen. It lasted about thirty minutes then just cleared up on its own.
The doctor said I had a blood clot in my brain that my body managed to dissolve before it could cause real damage. He wants me to see a neurologist for more tests to figure out where the clot came from.
I’ll definitely see a specialist tomorrow or early next week to talk things through, but there's a catch: I'm traveling in a foreign country without health insurance, so everything is incredibly expensive. Plus, the doc yesterday mentioned that in many cases like this, it happens once and never again, and even after all the testing, they often have no idea why.
Given all that, I'm wondering how much of this is actually necessary or urgent. I'm young, healthy, haven't had a major surgery in over 20 years, and there's no history of this kind of thing in my family.

I’d start by running every possible test right away. You can't really make any reliable predictions until you actually clear up what's causing this. If the neurologist and standard blood work don't turn up anything, it might be worth looking into an atrial septal defect or some kind of heart arrhythmia—which means a cardiologist should definitely be on the list. Both of those issues can cause clots even in young, otherwise healthy people, and they’re notoriously easy to miss. If the routine panels come back clean, that’s when you start digging deeper there. Also, leg vein health is a factor, since clots can form there too, though that seems less likely in this case.