Unfortunately, we can't diagnose what's going on over the internet. Only a doctor who is familiar with your medical history as well as has the ability to examine you personally can give you the information you're looking for. I'm really sorry.
Here is a link that might be helpful that talks about the stges of a Migraine attack:
To add a bit of information to what Ellen said - Yes, itis possible for a Migraine to be pain-free but still make you very sick.
When Migraines occur with out the headache phase, they're called "acephalgic" or "silent." Here's some information, Acephalgic or Silent Migraine – The Basics.
Of course, the only person who can tell you if this is what's happening to you is your doctor, but the information above may give you and your doctor some information to discuss.
Please let us know what you find out?
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