Is it possible to have migraines without a headache?

For the past several months I’ve been feeling light headed, nausea, and sometimes a pounding headache. I went to a neurologist and he diagnosed me with migraines and prescribed me nortriptyline 10mg. I’m only taking 2 pills at night slowly increasing dosage.

It seemed to have worked but today I started feeling very light headed again. I didn’t take my pills yesterday, I wonder if that’s why.

But sometimes I feel light headed and nausea without any head pain. Could that still be a migraine?