Can you guys help me with my eyeball question?

i have a eye thing called an astigmatism. but the kind that i has causes migraines, and severe nausea. i tried searching for an explanation weeks ago and didn't come up with anything. one minute i will see fine, but then the next minute i will have something causing me to have blind spots in my eyes. its trippy though because it causes the colors to look like swirling colors and shapes. i can even see it when i close my eyes. i couple years ago i saw an optometrist and i explained what was going on, and they said they didn't understand what i was talking about... just wondering iif someone had the same thing happen to them as me, or if there was an explanation to what my eye is trying to do to itself. thanks