My daughter developed migraines at the same point in her recovery (five months). We finally figured out hers were triggered by normal hormonal shifts, but holy cow they were debilitating. I don't know if this will help you, but a midwife we know suggested she eat some form of protein every single waking hour with 4 or more oz of water. So she would have a handful of plain nuts, or a quarter of a sandwich, etc. It really helped.

The migraines stopped once her PCS sort of calmed down. All the best.