Hi Anna
I use to get these types of migraines too, they are scary and awful. I found out that mine were related to my sinuses. When I feel this type of headache coming now, I immediately use my 'steamer' with a few drops of tea tree oil and usually* the headache retreats.
I try to stay au natural in my treatments but if a 'damnbuster' (that's my nickname for a really bad migraine) is on the way nothing is going to stop it.
Maybe you could have your eyes checked too? Ask them to check your intra ocular pressures.
Try to stay calm, anxiety and panic makes things worse. This I know :)
Sounds like an occular migraine. I get them a lot. Its not fun!