You've been through a lot.

I hope the symptoms will calm down as your body heals more. They can do so much these days it just amazes me. My sister had an aneurysm decades ago and there was only extremely invasive surgery available.
Could it be depression you're experiencing from all you went through? Your description sounds like me when my anti-depressants lose effectiveness.
And if that's what it is, it would be easy to treat with meds and/or counseling.
I used to get migraines almost daily and whenever it reoccurs I take Topamax daily, a very low dose, to get the headaches under control. That particular med makes me very tired though so I only use it as a last resort.
Anyway, your evaluation is a long way off. Can you see your PCP for something for the headaches? Or maybe the surgeon needs to know what's happening in case you need a re-check? Take care and keep us posted.