9 tablets Nortriptyline does that mean 90mg ? You should start seeing benefits from week 2-3 and full benefit by week 6. I am on a similar medicine on Amitriptyline.
The floaters and visual blurring could be the aura related to the migraine playing games with you eyes. Don’t waste time with the optomterist it is not going to turn up anything.
Do your VRT only when you are feeling alright. Personally i have not seen any benefit from it but still do it to build confidence.
In addition to the diet stay hydrated. Drink lots of water even if you are not thirsty. Dry mouth is know to happen Nortriptyline and so you will be thirsty.
Hang in there. You will feel better. Go for long walks it helps you relax. PM me if you feel like chatting.